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Section 1: DEFM14A (DEFM14A)


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INDEX TO THE CONSOLIDATED FINANCIAL STATEMENTS OF HENDERSON
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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of
the Securities Exchange Act of 1934 (Amendment No.          )

Filed by the Registrant ý

Filed by a Party other than the Registrant o

Check the appropriate box:

o

 

Preliminary Proxy Statement

o

 

Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

ý

 

Definitive Proxy Statement

o

 

Definitive Additional Materials

o

 

Soliciting Material under §240.14a-12

 

Janus Capital Group Inc.

(Name of Registrant as Specified In Its Charter)

 

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

ý

 

No fee required.

o

 

Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.
    (1)   Title of each class of securities to which transaction applies:
        
 
    (2)   Aggregate number of securities to which transaction applies:
        
 
    (3)   Per unit price or other underlying value of transaction computed pursuant to Exchange Act Rule 0-11 (set forth the amount on which the filing fee is calculated and state how it was determined):
        
 
    (4)   Proposed maximum aggregate value of transaction:
        
 
    (5)   Total fee paid:
        
 

o

 

Fee paid previously with preliminary materials.

o

 

Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

 

 

(1)

 

Amount Previously Paid:
        
 
    (2)   Form, Schedule or Registration Statement No.:
        
 
    (3)   Filing Party:
        
 
    (4)   Date Filed:
        
 

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LOGO


MERGER PROPOSED—YOUR VOTE IS VERY IMPORTANT

Dear Stockholder:

            You are cordially invited to attend a special meeting of the stockholders, which we refer to as the Janus special meeting, of Janus Capital Group Inc., which we refer to as Janus. The Janus special meeting, is to be held on April 25, 2017 at 10:00 a.m. local time at the JW Marriott Hotel, 150 Clayton Lane, Denver, Colorado.

            As previously announced, Janus, Henderson Group plc, which we refer to as Henderson, and Horizon Orbit Corp., a Delaware corporation and a direct and wholly owned subsidiary of Henderson, which we refer to as Merger Sub, entered into an Agreement and Plan of Merger, dated as of October 3, 2016, which we refer to as the merger agreement. Pursuant to the terms of the merger agreement, Merger Sub will merge with and into Janus, with Janus surviving such merger as a direct and wholly owned subsidiary of Henderson, which we refer to as the merger. Upon closing of the merger, Henderson will be the parent holding company for the combined group and will be renamed Janus Henderson Group plc, which we refer to as Janus Henderson. We believe that this merger of Janus and Henderson accelerates both businesses' strategic objectives for growth, diversification, and the creation of a truly global active investment manager. We believe that the merger will benefit both the Janus stockholders and the Henderson shareholders and we ask for your support in voting for the proposals at the Janus special meeting.

            Upon closing of the merger, a holder of Janus common stock will be entitled to receive 4.7190 fully paid and non-assessable Henderson ordinary shares for each share of Janus common stock that it holds, which we refer to as the exchange ratio, plus cash in lieu of any fractional shares based on then prevailing market prices, subject to the following adjustments. Effective immediately prior to the closing of the merger, Henderson will implement a share consolidation of Henderson ordinary shares, which we refer to as the share consolidation, at a ratio of one Janus Henderson ordinary share (or CDI, as applicable) for every 10 Henderson ordinary shares (or CDIs, as applicable) outstanding (so that at closing of the merger each Janus stockholder will receive 0.4719 Janus Henderson ordinary shares for each share of Janus common stock). In addition, subject to approval by the Henderson shareholders at the Henderson shareholder meeting, effective upon the date of the Henderson shareholder meeting, the par value of Henderson ordinary shares will be redenominated from pounds sterling into U.S. dollars. Following the redenomination, subject to approval by the Henderson shareholders at the Henderson shareholders meeting, upon completion of certain registration procedures with the Jersey Registrar of Companies, the par value of Henderson ordinary shares will be reduced to ensure that the par value is a round number. Based on Henderson's and Janus's respective fully diluted shares as of the signing date, it is expected that the exchange ratio will result in Henderson shareholders and Janus stockholders owning approximately 57% and 43% of Janus Henderson, respectively, immediately following the effective time of the merger, which we refer to as the effective time, excluding the conditional options granted to Dai-ichi, which are subject to closing of the merger and Henderson shareholders' approval. Shares of Janus common stock are currently traded on the New York Stock Exchange, which we refer to as NYSE, under the symbol "JNS" and Henderson ordinary shares are currently traded on the London Stock Exchange, which we refer to as the LSE, under the symbol "HGG", and Henderson maintains a listing of CHESS Depositary Interests, which we refer to as CDIs, each representing a beneficial interest in one Henderson ordinary share, on the ASX Limited, which we refer to as ASX, under the ticker symbol "HGG". We expect that, subject to shareholder approval, Henderson ordinary shares will be delisted from the LSE, ordinary shares of Janus Henderson, which we refer to as the Janus Henderson ordinary shares, will be listed on the NYSE under the ticker symbol "JHG" and the CDIs will remain quoted and traded on the financial market operated by ASX under the ticker symbol "HGG" for a short period of time following closing of the merger and then under the new ticker symbol "JHG".

            On September 30, 2016, the last trading day prior to the public announcement of the merger, for Henderson ordinary shares, the closing price on the LSE was 232.00 pence per share and, for shares of Janus common stock, the closing price on the NYSE was $14.01 per share. On September 30, 2016, the exchange rate for pounds sterling was $1.2972 per pound sterling as reported by Bloomberg. The implied value of the merger consideration payable in respect of each share of Janus common stock was 1,094.81 pence, or $14.20 in dollar equivalent. The total merger consideration as of the date immediately prior to the public announcement of the merger, based on 179,762,551 diluted shares of Janus common stock, was $2,552,960,673. On March 17, 2017, the latest practicable date before the date of this proxy statement/prospectus, for Henderson ordinary shares, the closing price on the LSE was 231.00 pence per share and, for shares of Janus common stock, the closing price on the NYSE was $12.82 per share. On March 17, 2017, the exchange rate for pounds sterling was $1.2376 per pound sterling as reported by Bloomberg. The implied value of the merger consideration payable in respect of each share of Janus common stock was 1,090.09 pence, or $13.49 in dollar equivalent. The total merger consideration as of March 17, 2017, based on 179,560,968 diluted shares of Janus common stock, was $2,422,446,509. The maximum number of Janus Henderson ordinary shares expected to be issued to Janus stockholders at the effective time is 86,970,130 (based on Janus shares of common stock outstanding as of March 15, 2017).

            We urge you to obtain current market quotations of Janus common stock and Henderson ordinary shares prior to casting your vote.

            At the Janus special meeting, you will be asked to consider and vote on:

            The Janus board unanimously recommends that Janus stockholders vote "FOR" each of the proposals to be considered at the Janus special meeting.

            We cannot complete the merger unless the Janus stockholders approve the Janus merger proposal.

            Your vote is very important, regardless of the number of shares you own. Whether or not you plan to attend the Janus special meeting, please promptly mark, sign and date the accompanying proxy and return it promptly in the enclosed postage-paid envelope, or authorize the individuals named on your proxy card to vote your shares by calling the toll-free telephone number or by using the Internet as described in the instructions included with your proxy card.

            The obligations of Janus and Henderson to complete the merger are subject to the satisfaction or waiver of several conditions set forth in the merger agreement. More information about Janus, Henderson, and the merger is contained in this proxy statement/prospectus.

            Janus encourages you to read this entire proxy statement/prospectus carefully, including the section entitled "Risk Factors" beginning on page 50.

Sincerely,

GRAPHIC

Glenn Schafer
Chairman of the Board

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities to be issued under this proxy statement/prospectus or determined that this proxy statement/prospectus is accurate or complete. Any representation to the contrary is a criminal offense.

This proxy statement/prospectus is dated March 21, 2017 and is first being mailed to the stockholders of Janus on or about March 21, 2017.


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LOGO

Janus Capital Group Inc.

NOTICE OF SPECIAL MEETING OF STOCKHOLDERS
To be held on April 25, 2017

TIME: 10:00 a.m. (local time) on April 25, 2017

PLACE: JW Marriott Hotel, 150 Clayton Lane, Denver, Colorado

ITEMS OF BUSINESS:

        The approval by Janus stockholders of the Janus merger proposal is required to complete the merger described in the accompanying proxy statement/prospectus.

        The Janus merger proposal, Janus compensation proposal, the amendment proposals and Janus adjournment proposal are described in the accompanying proxy statement/prospectus, which you should read carefully in its entirety before you vote.


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        The proxy statement/prospectus accompanying this notice, including the annexes thereto, contains further information with respect to the business to be transacted at the special meeting of the Janus stockholders, which we refer to as the Janus special meeting. We urge you to read the proxy statement/prospectus, including any documents incorporated by reference, and the annexes carefully and in their entirety. Janus will transact no other business at the Janus special meeting except such business as may properly be brought before the Janus special meeting or any adjournments or postponements thereof. Please refer to the proxy statement/prospectus of which this notice forms a part for further information with respect to the business to be transacted at the Janus special meeting.

BOARD OF DIRECTORS' RECOMMENDATION:

        After careful consideration, the Janus board, on October 1, 2016, unanimously approved the merger agreement and determined that entering into the merger agreement and consummating the transactions contemplated thereby are advisable and fair to and in the best interests of Janus and its stockholders.

        The Janus board unanimously recommends that the Janus stockholders vote "FOR" each of the Janus merger proposal, the Janus compensation proposal, the amendment proposals and the Janus adjournment proposal.

WHO MAY VOTE:

        Only holders of record of Janus common stock at the close of business on March 15, 2017, the record date for voting at the Janus special meeting, which we refer to as the record date, are entitled to vote at the Janus special meeting. On March 15, 2017, 184,297,796 shares of Janus common stock were issued and outstanding. Each share of Janus common stock is entitled to one vote.

        Persons present at the start of the Janus special meeting and representing in person or by proxy in excess of 50% of the total issued shares in Janus common stock entitled to vote at the Janus special meeting shall form a quorum for the transaction of business at the Janus special meeting. The Janus common stock represented by any proxy in the enclosed form will be voted in accordance with the instructions given on the proxy if the proxy is properly executed and is received by Janus prior to the close of voting at the Janus special meeting or any adjournment or postponement thereof. Any proxies returned without instructions will be voted FOR the proposals set forth on this Notice of Special Meeting of Stockholders.

        All stockholders will need proof of ownership of shares in Janus, and may be asked to present a form of personal photo identification, in order to be admitted to the Janus special meeting. In addition, if your shares of Janus common stock are held in the name of your broker, bank, or other nominee and you wish to attend the Janus special meeting, you must bring an account statement or letter from the broker, bank, or other nominee indicating that you were the owner of the shares on the record date.

VOTE REQUIRED FOR APPROVAL:

        Your vote is very important. We cannot complete the merger without the approval of the Janus merger proposal.

        Assuming a quorum is present, approval of the Janus merger proposal requires the affirmative vote of the holders of a majority of all outstanding shares of Janus common stock entitled to vote on the Janus merger proposal. Assuming a quorum is present, approval of each of the amendment proposals requires the affirmative vote of a majority of stockholders present, in person or represented by proxy, and entitled to vote at the Janus special meeting. Assuming a quorum is present, approval of the Janus compensation proposal requires the affirmative vote of a majority of stockholders present, in person or represented by proxy, and entitled to vote at the Janus special meeting. Assuming a quorum is present, approval of the Janus adjournment proposal requires the affirmative vote of a majority of stockholders present, in person or represented by proxy, and entitled to vote at the Janus special meeting.


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        Whether or not you plan to attend the Janus special meeting, please promptly mark, sign and date the accompanying proxy and return it promptly in the enclosed postage-paid envelope, or authorize the individuals named on your proxy card to vote your shares by calling the toll-free telephone number included with your proxy card or by using the Internet. If your shares are held in the name of a broker or other nominee, please follow the instructions on a voting instruction card furnished by the record holder.

Sincerely,

GRAPHIC

Glenn Schafer
Chairman of the Board


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ABOUT THIS PROXY STATEMENT/PROSPECTUS

        This proxy statement/prospectus, which forms part of a registration statement on Form F-4 filed with the U.S. Securities and Exchange Commission, which we refer to as the SEC, by Henderson, constitutes a prospectus of Henderson under Section 5 of the Securities Act with respect to the Henderson ordinary shares to be issued to Janus stockholders pursuant to the merger agreement. This proxy statement/prospectus also constitutes a proxy statement under Section 14(a) of the Securities Exchange Act of 1934, as amended, which we refer to as the Exchange Act only with respect to Janus stockholders. It also constitutes a notice of meeting with respect to the special meeting of Janus stockholders, which we refer to as the Janus special meeting.

        No one has been authorized to provide you with information that is different from that contained in, or incorporated by reference into, this proxy statement/prospectus. This proxy statement/prospectus is dated March 21, 2017. You should not assume that the information contained in, or incorporated by reference into, this proxy statement/prospectus is accurate as of any date other than that date. Neither our mailing of this proxy statement/prospectus to Janus stockholders, nor the issuance by Henderson of Henderson ordinary shares in connection with the merger, will create any implication to the contrary.

        The information in this proxy statement/prospectus is subject to completion. A registration statement relating to the securities described in this proxy statement/prospectus has been filed with the Securities and Exchange Commission. These securities may not be sold nor may offers to buy these securities be accepted prior to the time the registration statement becomes effective. This proxy statement/prospectus does not constitute an offer to sell, or a solicitation of an offer to buy, any securities, or the solicitation of a proxy, in any jurisdiction to or from any person to whom it is unlawful to make any such offer or solicitation in such jurisdiction, nor shall there be any sale of these securities in any jurisdiction, in which such offer would be unlawful prior to registration under the securities laws of such jurisdiction. Information contained in this proxy statement/prospectus regarding Janus has been provided by Janus and information contained in this proxy statement/prospectus regarding Henderson has been provided by Henderson.

        Unless otherwise indicated or as the context otherwise requires, each reference in this proxy statement/prospectus to:


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CURRENCIES

        In this proxy statement/prospectus, unless otherwise specified or the context otherwise requires:


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REFERENCE TO ADDITIONAL INFORMATION

        This proxy statement/prospectus incorporates important business and financial information about Janus from other documents that are not included in or delivered with this proxy statement/prospectus. This information is available to you without charge upon your request. You can obtain the documents incorporated by reference into this proxy statement/prospectus by requesting them in writing or by telephone from Janus at the following addresses and telephone numbers:

JANUS CAPITAL GROUP INC.
151 Detroit Street
Denver, Colorado 80206
+1 (303) 333-3963
Attention: Investor Relations

        Investors may also consult Janus's website for more information concerning the merger described in this proxy statement/prospectus. Janus's website is www.janus.com. Information included on the Janus website is not incorporated by reference into this proxy statement/prospectus.

        If you would like to request any documents, please do so by April 18, 2017 in order to receive them before the Janus special meeting.

        For more information, see "Where You Can Find More Information" beginning on page 300.


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TABLE OF CONTENTS

QUESTIONS AND ANSWERS

  1

About the Merger

  1

About the Special Meeting

  9

SUMMARY

  17

The Companies

  17

The Merger and the Merger Agreement

  18

De-listing from LSE and Listing on NYSE of Henderson ordinary shares; De-listing from NYSE and Deregistration of Janus common stock

  33

Name Change

  34

Janus Henderson Amended Memorandum and Articles of Association

  34

Henderson Foreign Private Issuer Status

  35

Pre-Closing Dividends; Post-Closing Dividend Policy

  35

Litigation Relating to the Transaction

  36

Comparison of Rights of Holders Janus Henderson Ordinary Shares and Shares of Janus Common Stock

  36

Jersey Company Considerations

  37

The Special Meeting

  37

Selected Consolidated Financial Information of Janus

  39

Selected Consolidated Financial Information of Henderson

  41

Summary Unaudited Pro Forma Condensed Combined Financial Information

  43

COMPARATIVE HISTORICAL AND PRO FORMA PER SHARE INFORMATION

  45

COMPARATIVE PER SHARE MARKET PRICE AND DIVIDEND INFORMATION

  46

EXCHANGE RATE INFORMATION

  48

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

  49

RISK FACTORS

  50

Risks Related to the Combined Business of Janus and Henderson

  50

Risks Related to Taxes

  64

Risks Related to the Business Combination

  67

Risks Related to the Merger

  71

Risks Related to Being a Jersey, Channel Islands Company Listing Ordinary Shares

  79

THE COMPANIES

  80

THE JANUS SPECIAL MEETING

  82

THE MERGER

  89

Effects of the Merger

  89

Background of the Merger

  89

Janus's Reasons for the Merger; Recommendation of the Janus Board

  99

Henderson's Reasons for the Merger

  104

Certain Estimated Synergies

  109

Henderson Management Forecast

  110

Opinion of Janus's Financial Advisor

  113

Interests of Janus Directors and Executive Officers in the Merger

  122

Merger Related Compensation

  127

Interests of Henderson Directors and Executive Officers in the Merger

  128

Certain Governance Matters Following the Merger

  130

U.S., U.K. and Jersey Tax Considerations

  131

Accounting Treatment

  142

Regulatory Approvals

  142

Exchange of Shares in the Merger

  142

Pre-Closing Dividends; Post-Closing Dividend Policy

  143

Share Consolidation

  144

Listing of Henderson ordinary shares on NYSE

  144

Delisting of Henderson Ordinary Shares from LSE

  145

De-Listing from NYSE and Deregistration of Janus Common Stock

  145

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No Appraisal Rights

  145

Litigation Relating to the Transaction

  145

Description of the Merger Agreement

  145

DAI-ICHI AGREEMENTS

  167

Amended and Restated Investment and Strategic Cooperation Agreement

  167

Option Agreement

  169

Voting and Support Agreement

  170

HENDERSON NAME CHANGE

  171

JANUS PROPOSAL 1: THE JANUS MERGER PROPOSAL

  172

JANUS PROPOSAL 2: THE JANUS COMPENSATION PROPOSAL

  173

JANUS PROPOSALS 3 THROUGH 7: THE AMENDMENT PROPOSALS

  174

JANUS PROPOSAL 8: POSSIBLE ADJOURNMENT TO SOLICIT ADDITIONAL PROXIES, IF NECESSARY OR APPROPRIATE

  175

BUSINESS OF HENDERSON

  176

Overview

  176

History and Strategic Transactions

  176

Industry Context

  177

Strengths

  177

Strategy

  178

AUM Diversification

  179

Investment Offerings

  179

Sales and Marketing

  180

Products and Services

  181

Intellectual Property

  181

Seasonality

  182

Competition

  182

Regulation

  182

Employees

  185

Property

  185

Litigation

  185

Corporate Information

  185

MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS OF HENDERSON

  186

CERTAIN RELATIONSHIPS AND RELATED PARTY TRANSACTIONS INVOLVING HENDERSON

  217

DESCRIPTION OF JANUS HENDERSON ORDINARY SHARES AND JANUS HENDERSON AMENDED ARTICLES OF ASSOCIATION

  218

Share Capital

  218

Janus Henderson Amended Articles

  219

Objects and Purpose

  219

Voting Rights

  219

Variation of Rights

  220

Transfer of Shares

  220

Forfeiture and Lien

  220

Dividends

  221

Alteration of Share Capital

  221

Purchase of Own Shares

  221

Shareholder Meetings

  221

Conditions of Admission

  222

Share Qualification for Janus Henderson Directors

  223

Janus Henderson Directors' Fees, Expenses, Pensions and Other Benefits

  223

Executive Directors

  223

Janus Henderson Directors' Retirement

  223

Removal of a Janus Henderson Director by Resolution

  224

Janus Henderson Directors' Interests

  224

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Duty of Confidentiality of Janus Henderson Directors

  224

Powers of the Janus Henderson Directors

  224

Communications with Members

  225

Disclosure of Shareholding Ownership

  225

Mandatory Bids

  226

CHESS Depositary Interests

  226

Jersey, Channel Islands Regulatory Matters

  229

REMUNERATION OF HENDERSON DIRECTORS AND SENIOR MANAGEMENT

  230

Remuneration Principles

  230

Total Remuneration

  231

Fixed Pay and Benefits

  232

Pension Entitlements and Contributions

  232

STI for the Year Ended December 31, 2016

  232

Financial Performance

  232

STI Performance Measures

  233

Strategic and Personal Contributions

  233

LTI Vesting in Respect of Performance Periods Ended in 2016

  238

LTI Awards Made during 2016

  239

Single Total Figure of Remuneration—Chairman

  240

Fees for the Board Chairman

  240

Outstanding LTI and Other Share Scheme Awards

  240

SECURITY OWNERSHIP OF CERTAIN BENEFICIAL HOLDERS, DIRECTORS AND MANAGEMENT OF HENDERSON

  243

Security Ownership of Major Shareholders

  243

Security Ownership of Henderson Directors and Senior Management

  243

SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS OF JANUS AND JANUS MANAGEMENT

  246

Security Ownership of Certain Beneficial Owners of Janus

  246

Security Ownership of Janus Management

  247

CORPORATE GOVERNANCE STRUCTURE OF JANUS HENDERSON AFTER THE MERGER

  248

Directors of Janus Henderson after the Merger

  248

Corporate Governance Profile of Janus Henderson

  252

Board Committees

  253

Corporate Governance Guidelines and Code of Business Conduct

  255

Senior Management of Janus Henderson

  255

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

  259

NOTES TO UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

  263

COMPARISON OF RIGHTS OF HOLDERS OF JANUS HENDERSON ORDINARY SHARES AND SHARES OF JANUS COMMON STOCK

  274

LEGAL MATTERS

  299

EXPERTS

  299

Henderson

  299

Janus

  299

WHERE YOU CAN FIND MORE INFORMATION

  300

SERVICE OF PROCESS AND ENFORCEABILITY OF CIVIL LIABILITIES UNDER U.S. SECURITIES LAWS

  302

INDEX TO THE CONSOLIDATED FINANCIAL STATEMENTS OF HENDERSON

 
F-1

ANNEX A

  A-1

ANNEX B

  B-1

ANNEX C

  C-1

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QUESTIONS AND ANSWERS

        The following are some questions that you, as a stockholder of Janus, may have regarding the merger and the other matters being considered at the Janus special meeting, as well as the answers to those questions. Janus urges you to read carefully the remainder of this proxy statement/prospectus because the information in this section does not provide all the information that might be important to you with respect to the merger and the other matters being considered at the Janus special meeting. Additional important information is also contained in the annexes to and the documents incorporated by reference into this proxy statement/prospectus. See "Where You Can Find More Information" beginning on page 300.

        Except where specifically noted, the following information and all other information contained in this proxy statement/prospectus does not give effect to the share consolidation described in the section entitled "The Merger—Share Consolidation", beginning on page 144 of this proxy statement/prospectus.

About the Merger

Q:
What is the proposed transaction on which I am being asked to vote?

A:
Janus and Henderson have agreed to the strategic combination of Janus and Henderson under the terms of the merger agreement that is described in this proxy statement/prospectus. Subject to the terms and conditions of the merger agreement, Merger Sub, a Delaware corporation and a direct and wholly owned subsidiary of Henderson, will be merged with and into Janus, with Janus surviving as a direct and wholly owned subsidiary of Henderson, which we refer to as the merger.

As a result of the merger, each issued and outstanding share of Janus common stock, par value $0.01, will be converted into the right to receive 4.7190 Henderson ordinary shares, par value £0.125, plus cash in lieu of any fractional shares based on then prevailing market prices, subject to the following adjustments. Effective immediately prior to the closing of the merger, subject to approval by the Henderson shareholders at the Henderson shareholder meeting, Henderson will implement the share consolidation at a ratio of one Janus Henderson ordinary share (or CDI, as applicable) for every 10 Henderson ordinary shares (or CDIs, as applicable) outstanding (so that at closing of the merger each Janus stockholder will receive 0.4719 Janus Henderson ordinary shares for each share of Janus common stock). In addition, subject to approval by the Henderson shareholders at the Henderson shareholder meeting, effective upon the date of the Henderson shareholder meeting, the par value of Henderson ordinary shares will be redenominated from pounds sterling into U.S. dollars. Following the redenomination, subject to approval by the Henderson shareholders at the Henderson shareholder meeting, upon completion of certain registration procedures with the Jersey Registrar of Companies, the par value of Henderson ordinary shares will be reduced to ensure that the par value is a round number.

Upon closing of the merger, Henderson will be the parent holding company for the combined group and will be renamed Janus Henderson Group plc, which we refer to as Janus Henderson or the combined company. Upon closing of the merger: (i) shares of Janus common stock will be delisted from the New York Stock Exchange, which we refer to as the NYSE, and shares of Janus common stock will be deregistered under the Exchange Act; and (ii) subject to the Henderson LSE de-listing approval being obtained, Henderson ordinary shares will be delisted from the London Stock Exchange, which we refer to as the LSE. Upon the closing, Janus Henderson ordinary shares will be listed for trading on the NYSE and CHESS Depositary Interests, which we refer to as the CDIs, each representing a beneficial interest in one Janus Henderson ordinary share, will continue to be quoted and traded on the financial market operated by ASX.

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Q:
Why is stockholder approval necessary and who is entitled to vote?

A:
This proxy statement/prospectus serves as the proxy statement through which Janus will solicit proxies to obtain the necessary stockholder approvals for the merger. It also serves as the prospectus by which Henderson will issue its ordinary shares as consideration in the merger.

Janus is holding a special meeting of stockholders, which we refer to as the Janus special meeting, in order to obtain the stockholder approval necessary to adopt the merger agreement. Janus stockholders will also be asked to approve the adjournment of the Janus special meeting (if necessary or appropriate to solicit additional proxies if there are not sufficient votes to approve the Janus stockholder proposals), to approve, by non-binding advisory vote, the compensation arrangements for Janus's named executive officers in connection with the merger, which compensation is summarized in the table in the section entitled "The Merger—Merger Related Compensation" beginning on page 127, and to approve, by non-binding advisory vote, certain amendments to the Henderson Memorandum of Association and Henderson Articles of Association. The approval of the foregoing compensation arrangements and amendments are not conditions to the completion of the merger and the merger will be consummated regardless of whether one or more of these approvals are obtained.

We will be unable to complete the merger unless, among other things, the Janus stockholders vote to adopt the merger agreement and the Henderson shareholders approve the merger, the Henderson share issuance proposal, the Henderson name change proposal, the Henderson amended articles proposal, the Henderson LSE de-listing proposal and the Henderson permitted dividend proposal.

You are receiving this proxy statement/prospectus because you were a holder of record of Janus common stock as of the close of business on March 15, 2017, the record date for the Janus special meeting, which we refer to as the record date.

This proxy statement/prospectus contains important information about the merger, the merger agreement (which is summarized below in the section entitled "The Merger—Description of the Merger Agreement" and a copy of which is attached as Annex A), the amended Memorandum of Association of Janus Henderson, which we refer to as the Janus Henderson Amended Memorandum, and the amended Articles of Association of Janus Henderson, which we refer to as the Janus Henderson Amended Articles (which are summarized below in the section entitled "Description of Janus Henderson Ordinary Shares and Janus Henderson Amended Articles of Association" and forms of which are attached as Annex B), and the Janus special meeting. You should read this information carefully and in its entirety.

The enclosed voting materials also allow you to vote your shares of Janus common stock without attending the Janus special meeting. Your vote is very important and we encourage you to submit your proxy as soon as possible.

Q:
What will Janus stockholders receive in the merger?

A:
If the merger is completed, pursuant to the merger agreement, Janus stockholders will be entitled to receive 4.7190, which we refer to as the exchange ratio, Henderson ordinary shares for each share of Janus common stock they hold at the effective time, which we refer to as the merger consideration. Effective immediately prior to the closing of the merger, subject to approval by the Henderson shareholders at the Henderson shareholder meeting, Henderson will implement the share consolidation at a ratio of one Janus Henderson ordinary share (or CDI, as applicable) for every 10 Henderson ordinary shares (or CDIs, as applicable) outstanding (so that at closing of the merger each Janus stockholder will receive 0.4719 Janus Henderson ordinary shares for each share of Janus common stock). Janus stockholders will not receive any fractional Henderson ordinary

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Q:
What will Henderson shareholders receive in the merger?

A:
If the merger is completed, Henderson shareholders will continue to hold their Janus Henderson ordinary shares or CDIs, as applicable, and will not receive any consideration in the merger.

Q:
What equity stake will former Janus stockholders and former Henderson shareholders hold in Janus Henderson?

A:
Under the merger agreement and pursuant to the exchange ratio, based on Henderson's and Janus's respective fully diluted shares as of the signing date, it is expected that Henderson shareholders and Janus stockholders will own approximately 57% and 43%, respectively, of the combined company's ordinary shares immediately following the effective time excluding any dilutative instruments issued to Dai-ichi in connection with the merger.

Q:
How do I calculate the value of the merger consideration?

A:
On September 30, 2016, the last trading day prior to the public announcement of the merger, for Henderson ordinary shares, the closing price on the LSE was 232.00 pence per share and, for shares of Janus common stock, the closing price on the NYSE was $14.01 per share. On September 30, 2016, the exchange rate for pounds sterling was $1.2972 per pound sterling as reported by Bloomberg. The implied value of the merger consideration payable in respect of each share of Janus common stock was 1,094.81 pence, or $14.20 in dollar equivalent. The total merger consideration as of the date immediately prior to the public announcement of the merger, based on 179,762,551 diluted shares of Janus common stock, was $2,552,960,673.

On December 31, 2016, for Henderson ordinary shares, the closing price on the LSE was 235.60 pence per share and, for shares of Janus common stock, the closing price on the NYSE was $13.27 per share. On December 31, 2016, the exchange rate for pounds sterling was $1.2340 per pound sterling as reported by Bloomberg. The implied value of the merger consideration payable in respect of each share of Janus common stock was 1,111.80 pence, or $13.72 in dollar equivalent. The total merger consideration as of December 31, 2016, based on 180,253,742 diluted shares of Janus common stock, was $2,473,003,394.

On March 17, 2017, the latest practicable date before the date of this proxy statement/prospectus, for Henderson ordinary shares, the closing price on the LSE was 231.00 pence per share and, for shares of Janus common stock, the closing price on the NYSE was $12.82 per share. On March 17, 2017, the exchange rate for pounds sterling was $1.2376 per pound sterling as reported by Bloomberg. The implied value of the merger consideration payable in respect of each share of Janus common stock was 1,090.09 pence, or $13.49 in dollar equivalent. The total merger consideration as of March 17, 2017, based on 179,560,968 diluted shares of Janus common stock, was $2,422,446,509.

We urge you to obtain current market quotations and currency exchange rates before voting your shares of Janus common stock.

The merger agreement does not contain any provision that would adjust the exchange ratio based on fluctuations in the market value of either the Janus common stock or Henderson ordinary shares or currency exchange rates between the signing date and the effective time. Because of this, the implied value of consideration to the Janus stockholders may fluctuate between now and closing of the merger. The value of the consideration to Janus stockholders will depend on the

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Q:
What do I need to do now to receive the merger consideration?

A:
After the merger is completed, Janus stockholders will each receive from the exchange agent instructions on how to surrender their book-entry shares in exchange for the merger consideration.

Q:
After the merger, where can I trade my Janus Henderson ordinary shares?

A:
It is a condition to the closing of the merger that the Janus Henderson ordinary shares will be approved for listing on the NYSE. At and as of the closing of the merger, it is expected that the Janus Henderson ordinary shares will be traded on the NYSE under the ticker symbol "JHG".

Subject to the Henderson LSE de-listing approval being obtained, Janus Henderson ordinary shares will not be traded on the LSE following the closing of the merger, but interests in Janus Henderson ordinary shares will continue to be quoted and traded on the financial market operated by ASX in the form of CDIs under the ticker symbol "HGG" for a short period of time following closing of the merger and then under the new ticker symbol "JHG".

Q:
Will I still be paid dividends prior to the merger?

A:
Janus has declared and paid to Janus stockholders quarterly cash dividends of US$0.11 and US$0.11 per share of Janus common stock for the third and fourth quarter of 2016, respectively. Janus also currently expects to declare and pay a dividend in respect of the first quarter of 2017 to Janus stockholders prior to closing of the merger.

Q:
Will I still be paid dividends after the merger?

A:
Janus Henderson is expected to continue to follow a progressive dividend policy, increasing the dividend broadly in-line with growth in adjusted operating income over the medium term and with a pay-out ratio consistent with Henderson's past practice. Following the closing of the merger, it is intended that Janus Henderson will declare dividends on a quarterly basis beginning with the second quarter of 2017.

However, the amount of dividends, if any, that are declared or paid to Janus Henderson shareholders in periods after closing of the merger cannot yet be determined and will depend on a number of factors. The Janus Henderson board will have sole discretion to determine whether any interim dividends will be declared, the amount of any such interim dividend, the amount of any final dividend recommended to its shareholders (which may be paid subject to the approval of Janus Henderson shareholders by way of an ordinary resolution) and when any dividend will be paid. We expect that such determination would be based on a number of considerations, including, but not limited to, Janus Henderson's results of operations, capital management plans, the market price of Janus Henderson ordinary shares, the combined company's access to capital markets, as well as legal requirements, industry practice and other factors deemed relevant by the Janus Henderson board. There can be no assurance that Janus Henderson shareholders will receive or be entitled to dividends commensurate with the historical dividends of Janus or Henderson. For a

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Q:
Who will serve as the directors and senior officers of the combined company?

A:
Under the terms of the merger agreement, at the effective time, the Janus Henderson board will consist initially of 12 directors. Six of the 12 directors will be persons that are current directors of Henderson: Andrew Formica, the current Chief Executive of Henderson, Richard Gillingwater, the current Chairman of Henderson, who will serve as Chairman of the Janus Henderson board, Sarah Arkle, Kalpana Desai, Kevin Dolan, and Angela Seymour-Jackson. Six of the 12 directors will be persons that are current directors of Janus: Richard Weil, the current Chief Executive Officer of Janus, Glenn Schafer, the current Chairman of Janus, who will serve as Deputy Chairman of the Janus Henderson board, Jeff Diermeier, Eugene Flood Jr., Larry Kochard and Tatsusaburo Yamamoto. Dai-ichi is entitled to nominate a director to the Janus Henderson board pursuant to the terms of the amended investment and cooperation agreement, whom we refer to as the Dai-ichi Representative. Mr. Yamamoto is the initial Dai-ichi Representative. Not less than four directors designated by each of Henderson and Janus will be "independent" in accordance with the standards of the NYSE and the Corporate Governance Principles and Recommendations issued by the ASX Corporate Governance Council in March 2014, which we refer to as the ASX Principles.

Under the terms of the merger agreement, at the effective time, Andrew Formica and Richard Weil each will become co-Chief Executive Officer of Janus Henderson. Also at the effective time, the individuals set forth below will become executive officers of Janus Henderson, serving in the respective offices set forth beside each individual's name below. The executive officers, together with the co-Chief Executive Officers, will constitute the executive committee of Janus Henderson.

Enrique Chang, Global Chief Investment Officer

Phil Wagstaff, Global Head of Distribution

Bruce Koepfgen, Head of North America

Rob Adams, Head of Asia Pacific

Jennifer McPeek, Chief Operating and Strategy Officer

Roger Thompson, Chief Financial Officer

David Kowalski, Chief Risk Officer

Jacqui Irvine, Group General Counsel and Company Secretary

Q:
Who is the exchange agent for the merger?

A:
Computershare Inc., is the exchange agent.

Q:
When do you expect the merger to be completed?

A:
Janus and Henderson are currently anticipating closing of the merger on May 30, 2017. However, the merger is subject to certain conditions, and it is possible that the merger will be completed at a later time, or not at all. For additional information on the regulatory approvals and clearances required to complete the merger, see the section entitled "The Merger—Regulatory Approvals" beginning on page 142. For additional information on the conditions to closing of the merger, see the section entitled "The Merger—Description of the Merger Agreement—Conditions to Closing of the Merger" beginning on page 160.

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Q:
What effects will the merger have on Janus and Henderson?

A:
Upon closing of the merger, Janus will cease to have its common stock traded publicly. Merger Sub will merge with and into Janus, with Janus surviving the merger as a direct and wholly owned subsidiary of Henderson. Following closing of the merger, the registration of the Janus common stock and the reporting obligations of Janus with respect to its common stock under the Exchange Act will be terminated. In addition, upon closing of the merger, shares of Janus common stock will no longer be listed on the NYSE or any other stock exchange or quotation system. Although current Janus stockholders will no longer be stockholders of Janus, they will have an indirect interest in Janus through their ownership of Janus Henderson ordinary shares. Subject to the Henderson LSE de-listing approval being obtained, upon closing of the merger, Henderson ordinary shares will be delisted from the LSE and the Janus Henderson ordinary shares will be listed on the NYSE. In addition, the Janus Henderson CDIs will continue to be quoted and traded on the financial market operated by ASX.

Q:
What are the implications to Janus stockholders of Henderson being a "foreign private issuer"?

A:
Following completion of the merger, Janus Henderson will be subject to the reporting requirements under the Exchange Act applicable to foreign private issuers. Notwithstanding the fact that Janus Henderson will be a foreign private issuer, Janus Henderson intends to file its annual report on Form 10-K and, starting with closing of the merger, to file quarterly reports on Form 10-Q and current reports on Form 8-K. As a foreign private issuer, Janus Henderson would be required to file an annual report on Form 20-F and to furnish reports on Form 6-K to the SEC regarding certain information required to be publicly disclosed by Janus Henderson. In addition, as a foreign private issuer, Janus Henderson will be exempt from certain rules under the Exchange Act, including the proxy rules, which impose certain disclosure and procedural requirements for proxy solicitations under Section 14 of the Exchange Act, and will not be required to comply with Regulation FD, which addresses certain restrictions on the selective disclosure of material information. In addition, among other matters, Janus Henderson's officers, directors and principal stockholders will be exempt from the reporting and "short-swing" profit recovery provisions of Section 16 of the Exchange Act and the rules under the Exchange Act with respect to their purchases and sales of Janus Henderson ordinary shares. If Janus Henderson loses its status as a foreign private issuer, it will no longer be exempt from such rules and, among other things, will be required to file periodic reports and financial statements as if it were a company incorporated in the United States.

Q:
What are the conditions to the closing of the merger?

A:
In addition to the adoption of the merger agreement by the Janus stockholders, the closing of the merger is subject to the satisfaction or waiver of a number of other conditions, including:

the approval of (i) the merger by the affirmative vote of a majority of the Henderson shareholders voting (in person or represented by proxy) at the Henderson shareholder meeting, (ii) the Henderson share issuance proposal by the affirmative vote of a majority of the Henderson shareholders voting (in person or represented by proxy) at the Henderson shareholder meeting, (iii) the Henderson amended articles proposal by the affirmative vote of two-thirds of the Henderson shareholders voting (in person or represented by proxy) at the Henderson shareholder meeting, (iv) the Henderson name change proposal by the affirmative vote of two-thirds of the Henderson shareholders voting (in person or represented by proxy) at the Henderson shareholder meeting, (v) the Henderson permitted dividend proposal by the affirmative vote of a majority of the Henderson shareholders voting (in person or represented by proxy) at the Henderson annual general shareholder meeting and (vi) the Henderson LSE de-listing proposal by the affirmative vote of three-fourths of the Henderson shareholders voting

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Q:
What will happen to outstanding Janus equity awards in the merger?

A:
The merger agreement generally provides for the conversion of Janus Options, Janus RSU Awards, Janus PSU Awards and Janus Restricted Share Awards into corresponding awards for a number of Janus Henderson ordinary shares, determined by multiplying the number of shares of Janus common stock subject to each Janus award by the exchange ratio (subject to adjustment to account for the share consolidation). The exercise price of the Janus Options following the conversion will be determined by dividing the per-share exercise price of the Janus Options by the exchange ratio,

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Q:
What will happen to the Janus Employee Stock Purchase Plan in the merger?

A:
The merger agreement generally provides that each outstanding award under Janus's Employee Stock Purchase Plan, which we refer to as the Janus ESPP, will be converted at the effective time into corresponding awards for a number of Janus Henderson ordinary shares on the same basis as the Janus Options, provided that Janus and Henderson will cooperate prior to the effective time to determine whether different treatment of the Janus ESPP is appropriate, which treatment may include termination of the Janus ESPP at the effective time of the merger. For additional information on the treatment of Janus equity awards, see the section entitled "The Merger—Description of the Merger Agreement—Merger Consideration" beginning on page 146.

Q:
Are there any risks relating to the merger, Janus's business or the combined business that I should consider?

A:
Yes. There are risks associated with all mergers. These risks are discussed in more detail in the section entitled "Risk Factors" beginning on page 50 and you should also refer to the section entitled "Cautionary Statement Regarding Forward-Looking Statements" beginning on page 49.

Q:
Are Janus stockholders entitled to appraisal rights?

A:
No. Under the General Corporation Law of the State of Delaware, which we refer to as the DGCL, no appraisal rights are available to Janus stockholders in connection with the merger.

Q:
Will Janus still have an annual stockholders' meeting in 2017?

A:
Janus does not expect to hold an annual stockholders' meeting in 2017 while the merger is pending, and it currently plans to delay its 2017 annual stockholders' meeting and only hold an annual meeting in 2017 if the merger is terminated.

Q:
What are the U.S. federal income tax consequences of the merger to U.S. holders of shares of Janus common stock?

A:
The parties intend the merger to be treated as a tax-free reorganization under section 368(a) of the Internal Revenue Code of 1986, as amended, which we refer to as the Code. In addition, provided that the fair market value of Henderson, at the time of the merger, equals or exceeds the fair market value of Janus, as specially determined for purposes of section 367 of the Code, the parties intend that the merger should not be subject to section 367(a)(1) of the Code.

Assuming that the merger is so treated, if you are a U.S. holder of Janus common stock and you exchange all of your Janus common stock for Henderson ordinary shares in the merger, you should not recognize any gain or loss with respect to your Janus common stock, except to the extent of any cash you may receive in lieu of a fractional share.

If section 367(a)(1) of the Code were to apply to the merger, however, which cannot be determined definitively until the closing of the merger, a U.S. holder of Janus common stock would recognize gain (but not loss) in an amount equal to the excess, if any, of the fair market value, as of the closing date of the merger, of Henderson ordinary shares received in the merger plus cash received in lieu of fractional shares, over such U.S. holder's basis in the shares of Janus common stock surrendered by the U.S. holder in the merger. Any gain so recognized would

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Q:
What are the U.S. federal income tax consequences of the merger to U.S. holders of Henderson ordinary shares?

A:
So long as section 7874 of the Code is not applicable to the merger, there are no U.S. federal income tax consequences of the merger to U.S. holders of Henderson ordinary shares unless they also hold Janus common stock. If section 7874 of the Code were to apply, there would be an indirect impact on Henderson shareholders because Janus Henderson could be treated as a U.S. corporation and therefore could be liable for substantial U.S. federal income tax on its operations and income following the merger. In addition, non-U.S. shareholders could be subject to U.S. withholding tax on the gross amount of any dividends paid by Janus Henderson to such shareholders. Finally, the ability to use tax attributes to offset certain income may be limited.

Based on currently available data, the parties do not expect section 7874 to apply to the merger, although this conclusion cannot be made definitively until the closing of the merger.

For a more complete description of section 7874 and the U.S. federal income tax consequences of the merger for U.S. holders of Henderson ordinary shares, please see the sections entitled "Risk Factors—Risks Relating to Taxes—The IRS may not agree with the conclusion that Janus Henderson is to be treated as a foreign corporation for U.S. federal income tax purposes following the merger or may assert that Janus Henderson is subject to certain adverse consequences for U.S. federal income tax purposes following the merger" beginning on page 64 and "The Merger—U.S., U.K. and Jersey Tax Considerations—U.S. Federal Income Tax Considerations for U.S. Holders" beginning on page 131.

About the Special Meeting

Q:
When and where will the Janus special meeting be held?

A:
The Janus special meeting will be held at JW Marriott Hotel, 150 Clayton Lane, Denver, Colorado on April 25, 2017, 10:00 a.m. (local time).

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Q:
Who is entitled to vote at the Janus special meeting?

A:
Only holders of record of Janus common stock at the close of business on March 15, 2017, the record date for voting at the Janus special meeting, are entitled to vote at the Janus special meeting.

Q:
How can I attend the Janus special meeting?

A:
All stockholders will need proof of ownership of shares in Janus, and may be asked to present a form of personal photo identification, in order to be admitted to the Janus special meeting. In addition, if your shares are held in the name of your broker, bank, or other nominee and you wish to attend the Janus special meeting, you must bring an account statement or letter from the broker, bank, or other nominee indicating that you were the owner of the shares on the record date.

Q:
What proposals will be considered at the Janus special meeting?

A:
At the Janus special meeting, Janus stockholders will be asked to consider and vote on (i) a proposal to adopt the merger agreement, which we refer to as the Janus merger proposal, (ii) a non-binding, advisory proposal to approve the compensation that may become payable to Janus's named executive officers in connection with the consummation of the merger, which we refer to as the Janus compensation proposal, (iii) (A) a non-binding, advisory proposal to approve an amendment to the Henderson Memorandum of Association implementing the share consolidation of Henderson ordinary shares at a ratio of one new Janus Henderson ordinary share (or CDI) for every 10 Henderson ordinary shares (or CDIs, as applicable) outstanding, to be implemented effective upon the closing of the merger, (B) a non-binding, advisory proposal to approve an amendment to the Henderson Memorandum of Association increasing the authorized share capital of the company from £274,363,847.00 to $720,000,000, (C) a non-binding, advisory proposal to approve an amendment to the Henderson Articles of Association removing preemptive rights for Janus Henderson shareholders on new issuances of Janus Henderson ordinary shares, (D) a non-binding, advisory proposal to approve an amendment to the Henderson Articles of Association removing the requirement that the Janus Henderson board seek the approval of Janus Henderson shareholders to issue Janus Henderson ordinary shares and (E) a non-binding, advisory proposal to approve an amendment to the Henderson Articles of Association requiring directors of Janus Henderson to be re-elected at each annual Janus Henderson shareholder meeting, which we refer to as the amendment proposals, and (iv) a proposal to adjourn the Janus special meeting, if necessary or appropriate, to obtain additional proxies if there are not sufficient votes to approve the Janus merger proposal, which we refer to as the Janus adjournment proposal. Janus will transact no other business at its special meeting except such business as may properly be brought before the Janus special meeting or any adjournment or postponement thereof.

Q:
How does the Janus board recommend that I vote?

A:
The Janus board unanimously approved the merger agreement and determined that the merger agreement and the transactions contemplated thereby, including the merger, are advisable and fair to and in the best interests of Janus and its stockholders.

The Janus board unanimously recommends that the Janus stockholders vote:

"FOR" the Janus merger proposal;

"FOR" the Janus compensation proposal;

"FOR" each of the amendment proposals; and

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Q:
How do I vote?

A:
If you are a holder of record of Janus common stock as of the close of business on the record date for the Janus special meeting, you may vote in person by attending the applicable special meeting or, to ensure your shares are represented at the applicable meeting, you may vote by:

accessing the Internet website specified on your proxy card;

calling the toll-free number specified on your proxy card; or

marking, signing, dating and returning the enclosed proxy card in the postage-paid envelope provided.

If your shares are held in street name, through a broker, bank, trustee or other nominee, please follow the instructions on a voting instruction card furnished by the record holder.

Q:
How do I vote shares of Janus common stock I hold through the Employee Stock Ownership Plan and/or the Kansas City Southern 401(k) Plan?

A:
Each participant in the Employee Stock Ownership Plan of Janus, which we refer to as the Janus ESOP, and the Kansas City Southern 401(k) Plan, which we refer to as the KCS 401(k) Plan, may instruct the respective trustees of these plans on how to vote the shares of Janus common stock held on behalf of the participant under such plans. The trustee of each plan must receive your voting instructions for the common stock allocated to your Janus ESOP or KCS 401(k) Plan account before April 21, 2017. If the trustee for the Janus ESOP or the KCS 401(k) Plan does not receive your voting instructions before April 21, 2017, it will vote those shares, subject to the requirements of the Employee Retirement Income Security Act of 1974, as amended, in the same proportion as the voting instructions that it receives from other Janus ESOP or KCS 401(k) Plan account holders (as applicable).

Q:
If I am a Janus stockholder and my shares are represented by physical stock certificates, should I send in my stock certificates now?

A:
No. After the merger is completed, you will receive a transmittal form with instructions for the surrender of your Janus stock certificates. Please do not send in your stock certificates with your proxy card.

Q:
What is a "broker non-vote"?

A:
Under NYSE rules, banks, brokers and other nominees may use their discretion to vote "uninstructed" shares (i.e., shares held of record by banks, brokerage firms or other nominees but with respect to which the beneficial owner of such shares has not provided instructions on how to vote on a particular proposal) with respect to matters that are considered to be "routine," but not with respect to "non-routine" matters. "Non-routine" matters are matters that may substantially affect the rights or privileges of stockholders, such as mergers, stockholder proposals, elections of directors (even if not contested), executive compensation (including any advisory stockholder votes on executive compensation) and certain corporate governance proposals, even if management-supported. A "broker non-vote" occurs on an item when (i) a broker, nominee or intermediary has discretionary authority to vote on one or more proposals to be voted on at a meeting of stockholders, but is not permitted to vote on other proposals without instructions from the beneficial owner of the shares and (ii) the beneficial owner fails to provide the broker, nominee or intermediary with such instructions. Because none of the proposals to be voted on at the Janus

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Q:
What vote is required to approve each Janus proposal?

A:
Proposal to Adopt the Merger Agreement by Janus Stockholders.    Approving the Janus merger proposal requires the affirmative vote of a majority of the outstanding shares of Janus common stock entitled to vote on the Janus merger proposal. Accordingly, a Janus stockholder's failure to submit a proxy card or to vote in person at the Janus special meeting, an abstention from voting, or a broker non-vote will have the same effect as a vote "AGAINST" the proposal to adopt the merger agreement.

Proposal Regarding Certain Merger-Related Executive Compensation Arrangements.    In accordance with Section 14A of the Exchange Act, Janus is providing stockholders with the opportunity to approve, by non-binding advisory vote, compensation payments for Janus's named executive officers in connection with the merger. Approving the Janus compensation proposal, on a non-binding advisory basis, requires the affirmative vote of a majority of Janus stockholders present, in person or represented by proxy, and entitled to vote at the Janus special meeting. Accordingly, abstentions of Janus stockholders present (in person or represented by proxy) at the Janus special meeting will have the same effect as a vote "AGAINST" the Janus compensation proposal. A Janus stockholder's failure to submit a proxy card will have no effect on the Janus compensation proposal. A Janus stockholder who attends the Janus special meeting but does not vote will have the same effect as a vote "AGAINST" the Janus compensation proposal.

Proposals Regarding Certain Amendments to the Henderson Memorandum of Association and Henderson Articles of Association.    Approving each of the amendment proposals, on a non-binding advisory basis, requires the affirmative vote of a majority of Janus stockholders present, in person or represented by proxy, and entitled to vote at the Janus special meeting. Accordingly, abstentions of Janus stockholders present (in person or represented by proxy) at the Janus special meeting will have the same effect as a vote "AGAINST" each of the amendment proposals. A Janus stockholder's failure to submit a proxy card will have no effect on the amendment proposals. A Janus stockholder who attends the Janus special meeting but does not vote will have the same effect as a vote "AGAINST" each of the amendment proposals.

Proposal to Adjourn the Janus special meeting by Janus stockholders.    Approving the Janus adjournment proposal (if necessary or appropriate to obtain additional proxies if there are not sufficient votes to adopt the merger agreement) requires the affirmative vote of a majority of Janus stockholders present, in person or represented by proxy, and entitled to vote at the Janus special meeting. Accordingly, abstentions of Janus stockholders present (in person or represented by proxy) at the Janus special meeting will have the same effect as a vote "AGAINST" the Janus compensation proposal.

Q:
How many votes do I have?

A:
You are entitled to cast one vote for each share of Janus common stock that you owned as of the close of business on the record date for the Janus special meeting. As of the close of business on March 15, 2017, there were 184,297,796 shares of Janus common stock issued and outstanding entitled to vote at the Janus special meeting.

Q:
Do the Janus stockholders have to vote on the Janus merger proposal at the Janus special meeting if the Janus board has changed its recommendation of the Janus merger proposal?

A:
Yes. Unless the merger agreement is terminated before the Janus special meeting, Janus will notify the Janus stockholders before the Janus special meeting if the Janus board has changed its

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Q:
What will happen if I am present at the Janus special meeting, in person or by proxy, and I fail to vote or I abstain from voting?

A:
Proposal to Adopt the Merger Agreement by Janus stockholders.    If you are a Janus stockholder and fail to vote, fail to instruct a broker or other nominee to vote, or abstain, it will have the same effect as a vote "AGAINST" the Janus merger proposal.

Proposal Regarding Certain Merger-Related Executive Compensation Arrangements.    If you are a Janus stockholder present at the Janus special meeting (in person or represented by proxy) and fail to vote or abstain, it will have the same effect as a vote "AGAINST" the Janus compensation proposal.

Proposals Regarding Certain Amendments to the Henderson Memorandum of Association and Henderson Articles of Association.    If you are a Janus stockholder present at the Janus special meeting (in person or represented by proxy) and fail to vote or abstain, it will have the same effect as a vote "AGAINST" each of the amendment proposals.

Proposal to Adjourn the Janus special meeting by Janus stockholders.    If you are a Janus stockholder present at the Janus special meeting (in person or represented by proxy) and fail to vote or abstain, it will have the same effect as a vote "AGAINST" the Janus adjournment proposal.

Q:
What constitutes a quorum?

A:
A quorum of stockholders is necessary to transact business at the Janus special meeting. A quorum exists if the holders of at least a majority of the shares of Janus common stock entitled to vote are present either in person or represented by proxy at the meeting. Abstentions and broker non-votes will be counted in determining whether a quorum exists. Because none of the proposals to be voted on at the Janus special meeting are routine matters for which brokers may have discretionary authority to vote, Janus does not expect any broker non-votes at the Janus special meeting.

Q:
If my shares are held in "street name" by my broker, will my broker automatically vote my shares for me?

A:
No. If you hold your shares in a stock brokerage account or if your shares are held by a bank or nominee, that is, in "street name", your broker, bank, trust company or other nominee cannot vote your shares on "non-routine" matters without instructions from you. You should instruct your broker, bank, trust company or other nominee as to how to vote your shares, following the directions provided by your broker, bank, trust company or other nominee to you. Please check the voting form used by your broker, bank, trust company or other nominee.

If you are a Janus stockholder and you do not provide your broker, bank, trust company or other nominee with instructions and your broker, bank, trust company or other nominee submits an unvoted proxy, your shares of Janus common stock will be counted for purposes of determining a quorum at the Janus special meeting, but will not be voted on any proposal on which your broker, bank, trust company or other nominee does not have discretionary authority.

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Q:
What will happen if I return my proxy card without indicating how to vote?

A:
If you are a registered holder of record and you return your signed proxy card but do not indicate your voting preferences, the persons named in the proxy card will vote the shares represented by that proxy as recommended by the Janus board.

Please note that you may not vote shares held in street name by returning a proxy card directly to Janus, or by voting in person at the Janus special meeting unless you provide a "legal proxy", which you must obtain from your broker, bank, trust company or other nominee.

If you are a Janus stockholder and you do not instruct your broker on how to vote your shares of Janus common stock, your broker may not vote your shares of Janus common stock, which will have the same effect as a vote "AGAINST" the Janus merger proposal but will have no effect on the Janus compensation proposal, the amendment proposals or the Janus adjournment proposal, assuming a quorum is present. However, because none of the proposals to be voted on at the Janus special meeting are routine matters for which brokers may have discretionary authority to vote, Janus does not expect any broker non-votes at the Janus special meeting.

Q:
Can I change my vote after I have returned a proxy or voting instruction card?

A:
Yes. You can change your vote or revoke your proxy at any time before it is exercised at the Janus special meeting by doing any of the following:

Deliver a written notice of revocation to the General Counsel and Secretary, Janus Capital Group Inc., 151 Detroit Street, Denver, Colorado 80206 by 5:00 p.m. Denver time on April 24, 2017.

Complete, sign, and timely submit a new proxy card with a later date.

Timely submit a proxy with new voting instructions using the telephone or Internet voting system.

Vote in person at the Janus special meeting.

Your attendance at the special meeting in and of itself will not revoke any proxy.

Q:
Are any Janus stockholders already committed to vote in favor of any of the special meeting proposals?

A:
Under a voting and support agreement with Dai-ichi and Henderson, which we call the "voting agreement," Dai-ichi has agreed to vote all of its shares of Janus common stock in favor of the Janus merger proposal and have granted to Henderson a proxy to vote its shares in favor of the Janus merger proposal. As of March 15, 2017, Dai-ichi beneficially owned (with sole or shared voting power) 36,382,545 shares, or 19.74%, of the Janus common stock outstanding and entitled to vote at the special meeting. For more information, see "Dai-ichi Agreements" beginning on page 167.

Q:
What happens if I transfer my Janus common stock before the Janus special meeting?

A:
The record date for the Janus special meeting is earlier than both the date of the Janus special meeting and the date that the merger is expected to be completed. If you transfer your shares of Janus common stock after the record date but before the Janus special meeting, you will retain your right to vote at the Janus special meeting. However, in order to receive the merger consideration you must hold your shares of Janus common stock through the closing of the merger.

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Q:
Who is the inspector of election?

A:
The Janus board has appointed David W. Grawemeyer, Amy J. Stefonick and Broadridge Financial Services to act as inspectors of election at the Janus special meeting.

Q:
Where can I find the voting results of the Janus special meeting?

A:
The preliminary voting results are expected to be announced at the Janus special meeting. In addition, within four business days following certification of the final voting results, Janus intends to furnish on Form 8-K the final voting results of its special meeting with the SEC.

Q:
What will happen if the Janus merger proposal to be considered at the Janus special meeting is not approved?

A:
As a condition to the closing of the merger, Janus stockholders must approve the Janus merger proposal. Closing of the merger is not conditioned or dependent on approval of any of the other proposals to be considered at the Janus special meeting. Under specified circumstances, Janus or Henderson may be required to pay to, or be entitled to receive from, the other party, a fee with respect to termination of the merger agreement, see "The Merger—Description of the Merger Agreement—Expenses and Termination Fees" beginning on page 163.

Q:
Why are Janus stockholders being asked to approve, on a non-binding advisory basis, the compensation that may be paid or become payable to Janus's named executive officers in connection with the closing of the merger?

A:
The rules promulgated by the SEC under Section 14A of the Exchange Act require Janus to seek a non-binding, advisory vote with respect to certain compensation that may be paid or become payable to Janus's named executive officers in "Janus Proposal 2: The Janus Compensation Proposal" beginning on page 173.

Q:
What will happen if Janus stockholders do not approve, on a non-binding advisory basis, the payments to Janus's named executive officers in connection with the closing of the merger?

A:
The votes on the Janus compensation proposal are votes separate and apart from the votes on the Janus merger proposal. Accordingly, Janus stockholders may vote in favor of the Janus merger proposal and not in favor of the Janus compensation proposal, or vice versa. Approval of the Janus compensation proposal is not a condition to consummation of the merger, and it is advisory in nature only, meaning it will not be binding on Janus.

Q:
Why are Janus stockholders being asked to approve, on a non-binding advisory basis, the amendments to the Henderson Memorandum of Association and Henderson Articles of Association?

A:
Each stockholder of Janus will become a shareholder of Janus Henderson upon completion of the merger and the ordinary shares of Janus Henderson received by the Janus stockholders will be governed by the Janus Henderson Amended Memorandum and Janus Henderson Amended Articles. Accordingly, Janus stockholders are being provided the opportunity to cast a non-binding advisory vote on several of the amendments to the Henderson Memorandum of Association and Henderson Articles of Association. As an advisory vote, none of these proposals is binding upon Janus or Henderson (or Janus Henderson), and approval of these proposals is not a condition to completion of the merger. However, Janus seeks the support of Janus stockholders and believes that stockholder support is appropriate because the Janus stockholders will become Janus Henderson shareholders upon completion of the merger. Accordingly, holders of Janus common stock are being asked to vote on the non-binding amendment proposals.

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Q:
What will happen if Janus stockholders do not approve, on a non-binding advisory basis, any of the amendments to the Henderson Memorandum of Association or Henderson Articles of Association?

A:
Approval by Janus stockholders of the amendment proposals is not a condition to completion of the merger. The votes by Janus stockholders with respect to the amendment proposals are advisory and will not be binding on Janus or Henderson (or Janus Henderson). If Henderson's shareholders approve the Janus Henderson Amended Memorandum and Janus Henderson Amended Articles, the Janus Henderson Amended Memorandum and Janus Henderson Amended Articles will be effective upon completion of the merger. See "Janus Proposals 3 through 7: The Amendment Proposals" beginning on page 174.

Q:
What do I need to do now?

A:
Carefully read and consider the information contained in, and incorporated by reference into, this proxy statement/prospectus, including its annexes.

If you are a holder of record, in order for your shares to be represented at the Janus special meeting, you must:

attend the Janus special meeting in person;

vote through the Internet or by telephone by following the instructions included on your proxy card; or

indicate on the enclosed proxy card how you would like to vote, sign and return the proxy card in the accompanying pre-addressed postage paid envelope.

If you hold your shares in street name, in order for your shares to be represented at the Janus special meeting, you should instruct your broker, bank, trust company or other nominee as to how to vote your shares, following the directions provided to you by your broker, bank, trust company or other nominee.

Q:
Who can help answer my questions?

A:
Janus stockholders who have questions about the merger agreement, the merger or the other matters to be voted on at the Janus special meeting, who need assistance submitting their proxy or voting shares or who desire additional copies of this proxy statement/prospectus or additional proxy cards should contact:

Contact info for Janus Proxy Solicitor
Georgeson LLC
Telephone: Toll Free: 888-565-5423
Email: [email protected]

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SUMMARY

        This summary highlights information contained elsewhere in this proxy statement/prospectus and may not contain all the information that is important to you. Henderson and Janus urge you to read carefully the remainder of this proxy statement/prospectus, including the attached annexes and the other documents to which we refer you herein and documents incorporated by reference into this proxy statement/prospectus, as this section does not provide all the information that might be important to you with respect to the merger and the other matters being considered at the Janus special meeting. See also the section entitled "Where You Can Find More Information" beginning on page 300. We have included page references to direct you to a more complete description of the topics presented in this summary.

        Except where specifically noted, the following information and all other information contained in this proxy statement/prospectus does not give effect to the share consolidation described in the section entitled "The Merger—Share Consolidation", beginning on page 144 of this proxy statement/prospectus.

The Companies

Janus Capital Group Inc. (see page 80)

Janus Capital Group Inc.
151 Detroit Street
Denver, CO 80206
United States of America
Telephone: +1 (303) 333-3963

        Janus Capital Group Inc., a Delaware corporation, provides investment management, administration, distribution and related services to financial advisors, individuals and institutional clients through mutual funds, separate accounts, other pooled investment vehicles, exchange-traded products and subadvised relationships (collectively referred to as "investment products") in both domestic and international markets. Over the last several years, Janus has expanded its business to become a more diversified manager with increased investment product offerings and distribution capabilities. Janus provides investment management competencies across a range of disciplines, including fundamental U.S. and global equities (growth and value), mathematical equities, fixed income and alternatives, through its subsidiaries, Janus Capital Management LLC, INTECH Investment Management LLC and Perkins Investment Management LLC. As of December 31, 2016, Janus's assets under management totaled $196.8 billion for mutual fund shareholders, clients and institutions around the globe.

        Shares of Janus common stock are listed on the NYSE under the symbol "JNS".

        Additional information about Janus and its subsidiaries is included in documents incorporated by reference in this proxy statement/prospectus. See "Where You Can Find More Information" beginning on page 300.

Henderson Group plc (see page 80)

Henderson Group plc
201 Bishopsgate
EC2M 3AE
United Kingdom
Telephone: +44 (0) 20 7818-1818

        Henderson Group plc, a company incorporated and registered in Jersey, Channel Islands, is an independent global asset manager, specializing in active investment across all major asset classes. It is a client-focused global business with over 1,000 employees worldwide, and assets under management of £101.0 billion as of December 31, 2016. Henderson has operations in the United Kingdom, which we

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refer to as the U.K., Continental Europe, North America, Latin America, Asia and Australia. Henderson focuses on active fund management by investment managers with unique individual perspectives, who are free to implement their own investment views, within a strong risk management framework.

        Henderson manages a broad range of actively managed investment products for institutional and retail investors across five capabilities: European Equities, Global Equities, Global Fixed Income, Multi-Asset, and Alternatives.

        Additional information about Henderson is included in the section entitled "Business of Henderson" beginning on page 176.

Horizon Orbit Corp. (see page 81)

Horizon Orbit Corp.

c/o Henderson Group plc
201 Bishopsgate
EC2M 3AE
United Kingdom
Telephone: +44 (0) 20 7818-1818

        Horizon Orbit Corp., which we refer to as Merger Sub, is a Delaware corporation directly and wholly owned by Henderson that was formed on September 23, 2016. To date, Merger Sub has not conducted any activities other than those incidental to its formation. Pursuant to the merger agreement, Merger Sub will be merged with and into Janus, with Janus surviving the merger as a direct and wholly owned subsidiary of Henderson.

The Merger and the Merger Agreement

        A copy of the merger agreement is attached as Annex A to this proxy statement/prospectus. Janus and Henderson encourage you to read the entire merger agreement carefully because it is the principal document governing the merger. For more information on the merger agreement, see the section entitled "The Merger" beginning on page 89.

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Effects of the Merger (see page 89)

        The organization of Janus and Henderson (simplified) before and after the merger is illustrated on this page and the following page:


Prior to the Merger

GRAPHIC


The Merger

GRAPHIC

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After the Merger

GRAPHIC

Merger Consideration (see page 146)

        Subject to the terms and conditions set forth in the merger agreement, at the effective time, each share of Janus common stock issued and outstanding immediately prior to the effective time will be cancelled and each holder of such share of Janus common stock will have the right to receive 4.7190 fully paid and non-assessable Henderson ordinary shares, plus cash in lieu of fractional Henderson ordinary shares, based on then prevailing market prices, without interest, which we refer to as the merger consideration. Effective immediately prior to closing of the merger, subject to approval by the Henderson shareholders at the Henderson shareholder meeting, Henderson will implement the share consolidation at a ratio of one Janus Henderson ordinary share (or CDI, as applicable) for every 10 Henderson ordinary shares (or CDIs, as applicable) outstanding (so that at closing of the merger each Janus stockholder will receive 0.4719 Janus Henderson ordinary shares for each share of Janus common stock). In addition, each share of common stock of Merger Sub, par value $0.01 per share, issued and outstanding immediately prior to the effective time will be cancelled and, in exchange for the cancellation and the funding of the merger consideration by Henderson, Janus, as the surviving corporation in the merger will issue an equivalent number of fully paid and non-assessable shares of common stock of Janus, par value $0.01 per share, all of which shares shall be held by Janus Henderson, and which shall constitute the only outstanding shares of common stock of Janus, as the surviving corporation, immediately following the effective time.

        The merger agreement does not contain any provision that would adjust the exchange ratio based on the fluctuations in the market value of either the Janus common stock or Henderson ordinary shares or currency exchange rates. Because of this, the implied value of consideration to the Janus stockholders may fluctuate between now and closing of the merger. The value of the consideration to Janus stockholders will depend on the market value of Henderson ordinary shares at the time the merger is completed and on currency exchange rates. However, the merger agreement provides that the merger consideration will be adjusted appropriately to reflect the effect of any stock/share split, reverse stock split, share consolidation (including the share consolidation), share subdivision, share bonus issue or stock/share dividend (including any dividend or distribution of securities convertible into the Henderson ordinary shares or Janus common stock, as applicable), reorganization, recapitalization, reclassification, combination, exchange of shares or other like change with respect to the number of

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shares of Henderson ordinary shares or Janus common stock issued and outstanding after October 3, 2016 and prior to the effective time.

        On September 30, 2016, the last trading day prior to the public announcement of the merger, for Henderson ordinary shares, the closing price on the LSE was 232.00 pence per share and, for shares of Janus common stock, the closing price on the NYSE was $14.01 per share. On September 30, 2016, the exchange rate for pounds sterling was $1.2972 per pound sterling as reported by Bloomberg. The implied value of the merger consideration payable in respect of each share of Janus common stock was 1,094.81 pence, or $14.20 in dollar equivalent. The total merger consideration as of the date immediately prior to the public announcement of the merger, based on 179,762,551 diluted shares of Janus common stock, was $2,552,960,673.

        On December 31, 2016, for Henderson ordinary shares, the closing price on the LSE was 235.60 pence per share and, for shares of Janus common stock, the closing price on the NYSE was $13.27 per share. On December 31, 2016, the exchange rate for pounds sterling was $1.2340 per pound sterling as reported by Bloomberg. The implied value of the merger consideration payable in respect of each share of Janus common stock was 1,111.80 pence, or $13.72 in dollar equivalent. The total merger consideration as of December 31, 2016, based on 180,253,742 diluted shares of Janus common stock, was $2,473,003,394.

        On March 17, 2017, the latest practicable date before the date of this proxy statement/prospectus, for Henderson ordinary shares, the closing price on the LSE was 231.00 pence per share and, for shares of Janus common stock, the closing price on the NYSE was $12.82 per share. On March 17, 2017, the exchange rate for pounds sterling was $1.2376 per pound sterling as reported by Bloomberg. The implied value of the merger consideration payable in respect of each share of Janus common stock was 1,090.09 pence, or $13.49 in dollar equivalent. The total merger consideration as of March 17, 2017, based on 179,560,968 diluted shares of Janus common stock, was $2,422,446,509.

        We urge you to obtain current market quotations and currency exchange rates before voting your shares of Janus common stock.

Share Consolidation (see page 144)

        Subject to approval by the Henderson shareholders at the Henderson shareholder meeting, upon the effectiveness of the Janus Henderson Amended Memorandum immediately prior to the effective time of the merger, which we refer to as the share consolidation effective time, the Henderson ordinary shares and CDIs outstanding immediately prior to the share consolidation effective time will be consolidated into a smaller number of shares or CDIs, as applicable, such that a Henderson shareholder will own one Janus Henderson ordinary share (or one Janus Henderson CDI) for each 10 issued Henderson ordinary shares (or CDIs, as applicable) held by that Henderson shareholder immediately prior to the share consolidation effective time.

        No fractional shares or CDIs will be issued in connection with the share consolidation. Fractional entitlements arising because a Henderson shareholder of record holds a number of pre-consolidation Henderson ordinary shares not evenly divisible by 10 will be aggregated with the number of shares allocated to the CDI depositary in excess of the total number of shares to which CDI holders would have been entitled had they been Henderson shareholders of record immediately prior to the share consolidation, and all such shares will be sold on the market for the best price reasonably obtainable. The net proceeds of such sale, after the deduction of the expenses of the sale (including any fees in relation to currency conversions), will be paid in due proportion to the relevant Henderson shareholders of record or CDI holders (as applicable), in the case of CDI holders, such that they are paid the amount that they would have received in respect of the sale of fractional shares had they been a Henderson shareholder of record immediately prior to the share consolidation.

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        The approval of the share consolidation by the Henderson shareholders at the Henderson shareholder meeting is inter-conditional with the approval of the merger, the Henderson share issuance proposal, the Henderson amended articles proposal, the Henderson name change proposal and the Henderson LSE de-listing proposal, which means that for any of such matters to take effect, they must all be passed.

        As a result of the share consolidation, and in accordance with the terms of the merger agreement, the exchange ratio (being 4.7190 existing Henderson ordinary shares for each share of Janus common stock) will be adjusted so that at closing of the merger each Janus stockholder will receive 0.4719 Janus Henderson ordinary shares for each share of Janus common stock.

        Janus stockholders will also be entitled to receive cash in lieu of any fractional entitlement to new Janus Henderson ordinary shares based on the then prevailing market price.

Treatment of Henderson Equity Awards (see page 128)

        All Henderson equity awards will remain outstanding in accordance with the terms and conditions under the applicable plan and award agreement in effect immediately prior to the effective time (subject to adjustment to account for the share consolidation). For additional information on these amended terms and conditions, see the sections entitled "The Merger—Interests of Henderson Directors and Executive Officers in the Merger" beginning on page 128.

Treatment of Janus Equity Awards (see page 146)

        The merger agreement provides that, as of the effective time (subject to adjustment to account for the share consolidation):

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U.S. Federal Income Tax Consequences of the Merger to U.S. Holders of Janus Common Stock (see page 131)

        The parties intend the merger to be treated as a tax-free reorganization under section 368(a) of the Code. In addition, provided that the fair market value of Henderson, at the time of the merger, equals or exceeds the fair market value of Janus, as specially determined for purposes of section 367 of the Code, the parties intend that the merger should not be subject to section 367(a)(1) of the Code.

        Assuming that the merger is so treated, if you are a U.S. holder of Janus common stock and you exchange all of your Janus common stock for Henderson ordinary shares in the merger, you should not recognize any gain or loss with respect to your Janus common stock, except to the extent of any cash you may receive in lieu of a fractional share.

        If section 367(a)(1) of the Code were to apply to the merger, however, which cannot be determined definitively until the closing of the merger, a U.S. holder of Janus common stock would recognize gain (but not loss) in an amount equal to the excess, if any, of the fair market value, as of the closing date of the merger, of Henderson ordinary shares received in the merger plus cash received in lieu of fractional shares, over such U.S. holder's basis in the shares of Janus common stock surrendered by the U.S. holder in the merger. Any gain so recognized would generally be long-term capital gain if the U.S. holder had held the Janus common stock for more than one year at the time the merger is completed.

        Janus has requested that Skadden render its opinion to Janus, which will be dated on or after the closing date of the merger and be based on certain facts, representations, covenants, and assumptions, that the merger should be treated as a tax-free reorganization under section 368(a) of the Code and that section 367(a)(1) should not apply to the merger. Whether such opinion can be given will depend on the facts as of the closing date. Moreover, if such opinion is rendered, there can be no assurance that the IRS will agree with the conclusions expressed therein. The obligation of Janus and Henderson to consummate the merger, however, is not conditioned upon the receipt of such opinion from Skadden or any other counsel, nor have the parties applied for a ruling from the IRS.

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        For a more complete description of the U.S. federal income tax consequences of the merger, please see the section entitled "The Merger—U.S., U.K. and Jersey Tax Considerations—U.S. Federal Income Tax Considerations for U.S. Holders" beginning on page 131.

        Determining the actual tax consequences of the merger to you may be complex and will depend on your specific situation. You should consult your tax advisor for a full understanding of the tax consequences of the merger to you.

Janus's Reasons for the Merger; Recommendation of the Janus Board (see page 99)

        After careful consideration, the Janus board, on October 1, 2016, unanimously approved the merger agreement and determined that entering into the merger agreement and consummating the transactions contemplated thereby are advisable and fair to, and in the best interests of, Janus and its stockholders. For factors considered by the Janus board in reaching its decision to approve the merger agreement, see the section entitled "The Merger—Janus's Reasons for the Merger; Recommendation of the Janus Board" beginning on page 99. The Janus board unanimously recommends that Janus stockholders vote "FOR" each of the Janus merger proposal, the Janus compensation proposal, the amendment proposals and the Janus adjournment proposal.

Opinion of Janus's Financial Advisor (see page 113)

        Janus retained Loeb Spencer House to act as its financial advisor in connection with the merger. At the meeting of the Janus board on October 1, 2016, Loeb Spencer House rendered its oral opinion to the Janus board that, as of such date and based upon and subject to the factors and assumptions set forth in its opinion, the exchange ratio in the merger was fair, from a financial point of view, to holders of Janus's common stock (other than Janus or any wholly-owned subsidiary of Janus or Henderson and its affiliates). Loeb Spencer House confirmed its October 1, 2016 oral opinion by delivering its written opinion to the Janus board, dated October 1, 2016, that, as of such date and based upon and subject to the factors and assumptions set forth in its opinion, the exchange ratio in the merger was fair, from a financial point of view, to holders of Janus common stock (other than Janus or any wholly-owned subsidiary of Janus or Henderson and its affiliates).

        The full text of the written opinion of Loeb Spencer House, dated October 1, 2016, which sets forth the assumptions made, matters considered and limits on the review undertaken, is attached as Annex C to this proxy statement/prospectus. Janus's stockholders are urged to read the opinion in its entirety. Loeb Spencer House's written opinion was addressed to the Janus board (in its capacity as such) in connection with and for the purposes of its evaluation of the merger, spoke only as of October 1, 2016, was directed only to the exchange ratio in the merger and did not address any other aspect of the merger. The opinion does not constitute a recommendation to any stockholder of Janus as to how such stockholder should vote with respect to the Janus merger proposal or any other matter.

        For further information, see the section of this proxy statement/prospectus entitled "The Merger—Opinion of Janus's Financial Advisor" beginning on page 113 of this proxy statement/prospectus and Annex C.

Interests of Henderson Directors and Executive Officers in the Merger (see page 128)

        In considering the recommendation of the Janus board that you vote to approve the Janus merger proposal, you should be aware that Henderson directors and officers have certain financial interests in the merger. The Janus board was aware of and considered these potential interests, among other matters, in evaluating and negotiating the merger agreement and in recommending to you that you vote to approve the Janus merger proposal. See "The Merger—Interests of Henderson Directors and Executive Officers in the Merger" beginning on page 128.

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Interests of Janus Directors and Executive Officers in the Merger (see page 122)

        In considering the recommendation of the Janus board that you vote to approve the Janus merger proposal, you should be aware that Janus directors and executive officers have certain financial interests in the merger that may be different from, or in addition to, those of Janus stockholders generally. The Janus board was aware of and considered these potential interests, among other matters, in evaluating and negotiating the merger agreement and in recommending to you that you vote to approve the Janus merger proposal. See "The Merger—Interests of Janus Directors and Executive Officers in the Merger" beginning on page 122.

Regulatory Approvals (see page 142)

U.S. Antitrust

        Under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and the rules and regulations promulgated thereunder by the U.S. Federal Trade Commission, which we refer to as the FTC, which we refer to as the HSR Act, the merger cannot be consummated until, among other things, notifications have been filed and certain information has been furnished to the FTC and the Antitrust Division of the U.S. Department of Justice, which we refer to as the Antitrust Division, and specified waiting period requirements have been satisfied. On October 27, 2016, Henderson and Janus each filed a Notification and Report Form pursuant to the HSR Act, which we refer to as the HSR Notification, with the FTC and the Antitrust Division. The transaction received early termination of the waiting period on November 23, 2016.

Other Regulatory Approvals

        The obligations of each of Janus and Henderson to effect the merger is also subject to obtaining other regulatory approvals in various jurisdictions in which Henderson and Janus operate their respective business, including obtaining (i) approval from FINRA pursuant to NASD Rule 1017, (ii) the required approvals from the FCA for Henderson to acquire control of each subsidiary of Janus that is authorized by the FCA pursuant to Section 189(4)(a) of FSMA, (iii) the approval by the JFSC of this proxy statement/prospectus, the registration statement of which this proxy statement/prospectus forms a part and any other relevant document deemed to be a prospectus pursuant to the Jersey Companies Law, and the issue by the JFSC of any consent required pursuant to the Control of Borrowing (Jersey) Order 1958 for Henderson to lawfully assume the Janus awards and plans, and (iv) consents, non-objections and/or approvals from the applicable governmental authorities in Canada, Hong Kong, Ireland, Singapore and Switzerland and, if applicable, Australia, India and Jersey, as well as obtaining consents, non-objections and/or approvals from the applicable governmental authorities in Jersey, Switzerland and, if applicable, Ireland necessary in connection with the transactions contemplated by the Dai-ichi agreements.

Certain Governance Matters Following the Merger (see page 130)

        Pursuant to the terms of the merger agreement, Janus and Henderson have agreed to certain governance related arrangements. Additional governance related arrangements agreed to by Janus and Henderson are set forth in the proposed Janus Henderson Amended Memorandum and Janus Henderson Amended Articles, the approval of which by Henderson shareholders is a mutual condition to the closing of the merger.

The Janus Henderson Co-Chief Executive Officers

        The merger agreement provides that, as of the effective time, Richard Weil, the current Chief Executive Officer of Janus, and Andrew Formica, the current Chief Executive of Henderson, each will become a co-Chief Executive Officer of Janus Henderson.

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The Janus Henderson Board

        Under the terms of the merger agreement, at the effective time, the Janus Henderson board will consist initially of 12 directors. Six of the 12 directors will be persons that are current directors of Henderson: Andrew Formica, the current Chief Executive of Henderson, Richard Gillingwater, the current Chairman of Henderson, who will serve as Chairman of the Janus Henderson board, Sarah Arkle, Kalpana Desai, Kevin Dolan, and Angela Seymour-Jackson. Six of the 12 directors will be persons that are current directors of Janus: Richard Weil, the current Chief Executive Officer of Janus, Glenn Schafer, the current Chairman of Janus, who will serve as Deputy Chairman of the Janus Henderson board, Jeff Diermeier, Eugene Flood Jr., Larry Kochard and Tatsusaburo Yamamoto. Dai-ichi is entitled to nominate a director to the Janus Henderson board pursuant to the terms of the amended investment and cooperation agreement. Mr. Yamamoto is the initial Dai-ichi Representative. Not less than four directors designated by each of Henderson and Janus will be "independent" in accordance with the standards of the NYSE and the ASX Principles.

        Under the terms of the merger agreement, after the effective time, the committees of the Janus Henderson board will consist of an Audit Committee, a Nominating/Corporate Governance Committee, a Compensation Committee and a Risk Committee. The existing Henderson board will select the initial chairman of the Nominating/Corporate Governance Committee and the Risk Committee. The existing Janus board will select the initial chairman of the Audit Committee and the Compensation Committee. Each of the existing Janus board and the existing Henderson board will select two members of the Nominating/Corporate Governance Committee, the Compensation Committee, the Audit Committee and the Risk Committee. Each member of the committees must qualify as "independent" in accordance with the standards of the NYSE and the ASX Principles.

The Janus Henderson Officers

        Under the terms of the merger agreement, at the effective time, the individuals set forth below will become executive officers of Janus Henderson, serving in the respective offices set forth beside each individual's name below. The executive officers, together with the co-Chief Executive Officers, will constitute the executive committee of Janus Henderson.

Janus Henderson Amended Memorandum and Janus Henderson Amended Articles

        As of the effective time, Janus Henderson will adopt the Janus Henderson Amended Memorandum and the Janus Henderson Amended Articles, the forms of which are attached to this proxy statement/prospectus as Annex B. As described above, approval of the Janus Henderson Amended Memorandum and the Janus Henderson Amended Articles requires the approval of not less than two thirds of the Henderson shareholders. It is a condition to the closing of the merger that the Henderson shareholders approve the Janus Henderson Amended Memorandum and the Janus Henderson Amended Articles.

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Closing of the Merger

        Janus and Henderson are currently anticipating closing of the merger on May 30, 2017, subject to the receipt of required stockholder and shareholder approvals and regulatory approvals and clearances and the satisfaction or waiver of the other closing conditions. However, it is possible that the merger may be completed at a later time or not at all.

Dai-ichi Agreements (see page 167)

Voting Agreement

        On October 3, 2016, Dai-ichi entered into a voting and support agreement with Janus and Henderson, pursuant to which Dai-ichi, among other things and subject to the terms and conditions thereof, agreed to vote in favor of the approval of the Janus merger proposal and the Janus adjournment proposal and against any alternative business combination transaction. As of March 15, 2017, Dai-ichi beneficially owned, in the aggregate, 36,382,545 shares of common stock, which represented approximately 19.74% of the issued and outstanding shares of Janus common stock on such date. See "Dai-ichi Agreements—Voting and Support Agreement" on page 170.

Amended and Restated Investment and Strategic Cooperation Agreement

        On October 3, 2016, Dai-ichi entered into an amended and restated investment and strategic cooperation agreement with Janus and Henderson, pursuant to which, among other things and subject to the terms and conditions thereof, Dai-ichi agrees to maintain a certain level of investments in investment products of Janus Henderson, as well as certain standstill obligations in respect of Janus Henderson ordinary shares and certain restrictions on the transfer of its Janus Henderson ordinary shares and receives the right to designate a representative to the Janus Henderson board. See "Dai-ichi Agreements—Amended and Restated Investment and Strategic Cooperation Agreement" beginning on page 167.

Option Agreement

        On October 3, 2016, Henderson and Dai-ichi entered into an option agreement pursuant to which, conditional on closing of the merger, Henderson will, subject to the terms and conditions therein, grant Dai-ichi: (i) 11 conditional options, each to subscribe for or purchase 500,000 Janus Henderson ordinary shares at a strike price of 2,997.2 pence per share (the terms of such options having been adjusted in accordance with the terms of the Dai-ichi option agreement to take account of the effect of the share consolidation), and (ii) subject to the approval of Henderson shareholders (to be sought at the Henderson shareholder meeting in relation to the merger), nine conditional options, each to subscribe for or purchase 500,000 Janus Henderson ordinary shares at a strike price of 2,997.2 pence per share (the terms of such options having been adjusted in accordance with the terms of the Dai-ichi option agreement to take account of the effect of the share consolidation). The price that Dai-ichi will pay at closing for the purchase of the options is £19.8 million (provided that, if the requisite Henderson shareholder approval is not obtained at the Henderson shareholder meeting in relation to the merger, no amount shall be due from Dai-ichi in respect of the nine unapproved options). In aggregate, the options sold to Dai-ichi would, if exercised at closing of the merger (and subject to relevant regulatory approvals), entitle Dai-ichi to purchase an additional approximately 5% of the ordinary shares of Janus Henderson.

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Conditions to Closing of the Merger (see page 160)

        The obligations of each of Janus and Henderson to effect the merger are subject to the satisfaction or waiver of all of the following conditions:

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        There can be no assurance as to when, or whether, the conditions to the merger will be satisfied or waived, or the merger will be completed.

No Solicitation of Alternative Proposals (see page 154)

        The merger agreement contains detailed provisions outlining the circumstances in which Janus and Henderson may respond to competing proposals received from third parties. Under reciprocal provisions, Janus and Henderson each have agreed not to, and not to authorize or permit any of its controlled affiliates or any of its or their officers, directors or employees to, and to use its reasonable best efforts to cause any investment banker, financial advisor, attorney, accountant or other representative retained by it or any of its controlled affiliates not to, directly or indirectly:

        If Janus or Henderson, at any time prior to obtaining approval of its stockholders or shareholders, respectively, receives "an unsolicited proposal" that its board of directors determines in good faith (after consultation with outside counsel and a financial advisor of U.S. or U.K. nationally recognized reputation) that any such proposal that did not result from a material breach of the non-solicitation obligations set forth in the merger agreement constitutes or could reasonably be expected to result in a

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"superior proposal" (as defined on page 155), then Janus or Henderson, as applicable, may, subject to their respective obligations to provide the other party with information about such proposal, as described below, take the following actions:

        Janus and Henderson have each also agreed to (i) notify the other party promptly, and in any event within 24 hours of receipt, of any request for substantive information or of any proposal relating to an alternative transaction, the material terms and conditions of such request or proposal (including any changes thereto) and the identity of the person making such request or proposal; (ii) keep the other party reasonably informed of the status and details (including amendments or proposed amendments) of any such request or proposal on a current basis; and (iii) provide the other party, as soon as reasonably practicable, copies of all material substantive correspondence and other material written materials exchanged with the person making the proposal that describes in any material respect any of the material terms or conditions of any such request or proposal. For more information on the no solicitation provisions in the merger agreement, see the section entitled "The Merger—Description of the Merger Agreement—No Solicitation of Alternative Proposals" beginning on page 154.

Changes in Board Recommendations (see page 155)

        Janus, through its board of directors, has agreed to recommend approval to its stockholders of the Janus merger proposal, and to include such recommendations in this proxy statement/prospectus. Henderson, through its board of directors, has agreed to recommend approval to its shareholders of the merger, the Henderson share issuance proposal, the Henderson name change proposal, the Henderson amended articles proposal, the Henderson LSE de-listing proposal, the Henderson option proposal and the Henderson permitted dividend proposal.

        Except as provided below, each of the Janus board and the Henderson board is not permitted to:

        However, prior to obtaining the relevant stockholder or shareholder approvals, as applicable, the Janus board or the Henderson board, as applicable, is permitted to make a change of recommendation, if:

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        Prior to making a change of recommendation in response to a superior proposal, the party doing so must provide the other party with at least four business days' written notice specifying the material terms and conditions of such proposal, identifying the person making such proposal and stating that it intends to take such action, or in the event of a subsequent modification to the material terms and conditions of such superior proposal, at least two business days' written notice advising such other party of the modification to such terms and conditions, so long as during such four or two business day notice period, as applicable, such party engages (to the extent requested by the other party) in good faith negotiations with the other party to amend the merger agreement in such a manner that the proposal to enter into an alternative transaction no longer constitutes a superior proposal.

        If either Janus or Henderson effects a change of recommendation, such party has no termination right and will be required to submit the Janus merger proposal (in case of Janus) or the merger proposal, the Henderson amended articles proposal, the Henderson name change proposal, the Henderson permitted dividend proposal and the Henderson LSE de-listing proposal (in case of Henderson) to a vote of their stockholders and shareholders, respectively, at their respective special and shareholder meetings unless the merger agreement is earlier terminated in accordance with its terms.

        The parties have agreed that, to the extent that the U.K. Panel on Takeovers and Mergers determines that any of the above provisions either require Henderson to take an action that is not permitted, or restrict Henderson from taking an action that is required, under Rule 21.2 of the U.K. City Code on Takeovers and Mergers, which we refer to as the City Code, such provision shall be disregarded in respect of both parties.

Termination of the Merger Agreement (see page 162)

        The merger agreement may be terminated at any time prior to the effective time, whether before or after receipt of the required stockholder or shareholder approvals, as applicable, including the following circumstances:

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        In addition, the merger agreement may be terminated by Janus or Henderson, at any time prior to the other party's special meeting or shareholder meeting, as applicable, if a "triggering event" (as defined on page 163) shall have occurred.

        See the section entitled "The Merger—Description of the Merger Agreement—Termination of the Merger Agreement" beginning on page 162 for a more complete discussion of the circumstances under which the merger agreement may be terminated.

Expenses and Termination Fees Relating to the Merger (see page 163)

        Generally, each party is required to pay all fees and expenses incurred by it in connection with the merger and the other transactions and agreements contemplated by the merger agreement, except that each of Henderson and Janus will bear and pay one-half of the costs and expenses (other than the fees and expenses of each party's attorneys and accountants, which shall be borne by the party incurring such expenses) incurred by Henderson and Janus in connection with (i) the filing, printing and mailing of this Form F-4 and this proxy statement (including SEC filing fees), (ii) the filing, printing and mailing of the Henderson Shareholder Circular and any Henderson U.K. Prospectus (including filing fees), (iii) the filings of the premerger notification and report forms under the HSR Act and similar laws of other jurisdictions (including filing fees) and (iv) obtaining the consents of the boards of trustees and shareholders of Janus-advised U.S. mutual funds of new investment advisory agreements with Janus to take effect at the closing of the merger (including the costs and expenses of the proxy solicitation of the Janus-advised U.S. mutual funds filing, printing and mailing of materials required to be distributed to shareholders, and legal counsel). However, under the terms of the merger agreement, Janus or Henderson, as the case may be, must pay to the other party a termination fee equal to $34,000,000 in immediately available funds, upon termination of the merger agreement under the following circumstances:

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        In addition, if either Janus or Henderson terminates the merger agreement in the event the Janus required stockholder approval (in the case of a termination by Henderson) or the Henderson required shareholder approvals (in the case of a termination by Janus) are not obtained, the party whose stockholders or shareholders, as applicable, failed to provide the requisite approval is required to pay the other party's expenses up to an amount equal to $10,000,000. The expense reimbursement is credited against any termination fee payable as described above.

        See the section entitled "The Merger—Description of the Merger Agreement—Expenses and Termination Fees" beginning on page 163 for a more complete discussion of the circumstances under which termination fees and expenses will be required to be paid.

Accounting Treatment (see page 142)

        The merger will be accounted for as a business combination under the United States Generally Accepted Accounting Principles, which we refer to as U.S. GAAP, (ASC 805, which we refer to as the Standard). The Standard requires as the first step in the application of acquisition accounting for one of the combining entities to be identified as the acquirer. Henderson will be treated as the acquiring entity for accounting purposes. In identifying Henderson as the acquiring entity for accounting purposes, Henderson took into account the voting rights of all equity instruments, the intended corporate governance structure of the combined company, and the size of each of the companies. In assessing the size of each of the companies, Henderson evaluated various metrics, including, but not limited to: market capitalization, revenue, operating profit, assets and assets under management. No single factor was the sole determinant in the overall conclusion that Henderson is the acquirer for accounting purposes, rather all factors were considered in arriving at such conclusion.

No Appraisal Rights Available (see page 145)

        Under the DGCL, no appraisal rights are available to Janus stockholders in connection with the merger.

De-listing from LSE and Listing on NYSE of Henderson ordinary shares; De-listing from NYSE and Deregistration of Janus common stock (see page 145)

        Henderson ordinary shares are currently listed on the premium segment of the Official List maintained by the U.K. Listing Authority, being the Financial Conduct Authority, which we refer to as the FCA, acting in its capacity as the authority for listing in the U.K., which we refer to as the UKLA, and admitted to trading on the main market for listed securities of the LSE. CDIs, each representing a beneficial interest in one Henderson ordinary share, are quoted and traded on the financial market operated by ASX. Shares of Janus common stock are currently listed and admitted to trading on the NYSE.

        Following the merger, ordinary shares of Janus Henderson will be listed and will be admitted to trading on the NYSE. Janus Henderson will also maintain its listing on the ASX and the quotation of

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its CDIs on the financial market operated by ASX, linked to the primary listing of Janus Henderson ordinary shares on the NYSE. Subject to the Henderson LSE de-listing approval being obtained, Henderson ordinary shares will be de-listed from the LSE upon closing of the merger.

        When the merger is completed, the shares of Janus common stock currently listed on the NYSE will cease to be quoted on the NYSE and will subsequently be deregistered under the Exchange Act.

Name Change (see page 171)

        It is a condition to the closing of the merger that the Henderson shareholders approve the Henderson name change. As of the effective time, Henderson will file for registration to change the name of Henderson from "Henderson Group plc" to "Janus Henderson Group plc".

Janus Henderson Amended Memorandum and Articles of Association (see page 218)

        As of the effective time, Janus Henderson will adopt the Janus Henderson Amended Memorandum and the Janus Henderson Amended Articles, the forms of which are attached to this proxy statement/prospectus as Annex B. Approval of the Janus Henderson Amended Memorandum and the Janus Henderson Amended Articles requires the approval of not less than two thirds of the Henderson shareholders. It is a condition to the closing of the merger that the Henderson shareholders approve the Janus Henderson Amended Memorandum and the Janus Henderson Amended Articles.

        Subject to approval by the Henderson shareholders at the Henderson shareholder meeting, the par value of Henderson ordinary shares will be redenominated from pounds sterling into U.S. dollars. The redenomination will be reflected in the updated version of the Henderson Memorandum of Association, which we refer to as the Henderson interim memorandum, that will replace the Henderson Memorandum of Association effective upon the date of the Henderson shareholder meeting.

        The Janus Henderson Amended Memorandum will replace the Henderson interim memorandum and will reflect the (i) changing of the company name from Henderson Group plc to Janus Henderson Group plc and (ii) increasing of the authorized share capital of the company from £274,363,847.00 to $720,000,000.

        The Janus Henderson Amended Articles will replace the Henderson Articles of Association and will have the effect of, among other things, (i) removing preemptive rights, (ii) removing the requirement to seek shareholder approval to issue shares, (iii) establishing that the number of directors of Janus Henderson shall be not less than three nor more than 12 (to reflect the agreed governance arrangements in the merger agreement), (iv) increasing the quorum required for a general shareholder meeting from two holders to holders representing at least one-third in nominal value of the issued shares, (v) requiring directors of Janus Henderson to be re-elected at each annual shareholder meeting and eliminating the right of the chairman to cast a tie-breaking vote, (vi) establishing that the record date for general shareholder meetings must be set no less than 10 days and no more than 60 days before the date fixed for the meeting, (vii) increasing the cap on the remuneration of the non-executive directors of Janus Henderson to $3,000,000 per annum (or any higher amount approved by Janus Henderson shareholders), (viii) adopting the disclosure requirements for beneficial ownership of the company's ordinary shares set forth in Section 13(d) of the Exchange Act, (ix) granting the Janus Henderson board the authority to impose certain restrictions on shareholders in the event a disclosure notice pertaining to information on beneficial ownership is not complied with, (x) requiring shareholders to provide certain information and comply with certain timing requirements when exercising their right under Jersey companies law to require the Janus Henderson board to call a shareholder meeting, (xi) removing certain provisions that reflect the UK Companies Act 2006 (which are not considered to be appropriate following closing of the merger as Janus Henderson will not be listed on the LSE), (xii) removing the ability to issue bearer shares, (xiii) permitting the Janus Henderson board to transfer amounts to the share premium account from any other account (other

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than the nominal capital account and capital redemption reserve) in connection with any employee share award or option schemes and (xiv) permitting Janus Henderson's ordinary shares to be traded via DTC.

Henderson Foreign Private Issuer Status (see page 70)

        Under U.S. securities laws, classification as a "foreign private issuer" depends on two tests—one based on the percentage of shares of the issuer held by U.S. residents and the other on the nature and extent of the issuer's business contacts with the United States, which we refer to as the U.S. A company incorporated under the laws of a foreign country will not qualify as a foreign private issuer if it fails both of the tests in the definition as of the last business day of its most recently completed second fiscal quarter.

        The shareholder test will be met if 50% or less of the outstanding voting securities of a non-U.S. domiciled company are held by U.S. residents. If more than 50% of a non-U.S. company's voting securities are held by U.S. residents, the determination of foreign private issuer status will depend upon the business contacts the issuer has with the U.S. The business contacts test will not be met if any one of the following are true with respect to a non-U.S. domiciled company: (i) the majority of its executive officers or directors are U.S. citizens or residents; (ii) 50% or more of its assets are located in the U.S.; or (iii) its business is administered principally in the U.S. If an issuer determines that it no longer meets the definition of a foreign private issuer, it must transition to domestic reporting status and it becomes subject to the reporting requirements for a domestic company beginning on the first day of its next fiscal year.

        Henderson currently qualifies as a foreign private issuer, or FPI, under the foregoing rules. As a result, Henderson qualifies for certain accommodations under the U.S. securities laws, including (i) being able to report its financial results in accordance with the International Financial Reporting Standards, which we refer to as IFRS, as adopted by the International Accounting Standards Board, which we refer to as the IASB, (ii) being subject to reduced disclosure requirements with respect to quarterly reporting and executive compensation, (iii) not being subject to the proxy rules under the Exchange Act, Section 16 under the Exchange Act or Regulation FD, and (iv) being able to follow certain home country rules in lieu of domestic company requirements under NYSE rules.

        Janus and Henderson currently anticipate that Janus Henderson may not satisfy the foreign private issuer test in the future. Following such time Janus Henderson will need to comply with all domestic company reporting requirements. However, even though Janus Henderson may avail itself of the accommodations for foreign private issuers, it currently intends to report its financial results in accordance with U.S. GAAP, to file annual reports on Form 10-K, to file interim reports on Form 10-Q upon closing of the merger, to begin filing current reports on Form 8-K upon closing of the merger and to generally follow the NYSE corporate governance rules applicable to domestic companies. Until it becomes obligated to report as a domestic company Janus Henderson intends to avail itself of the exemptions from application of the proxy rules under the Exchange Act, Section 16 of the Exchange Act, Regulation FD and certain other rules applicable to domestic companies.

Pre-Closing Dividends; Post-Closing Dividend Policy (see page 143)

        Prior to the closing of the merger, Henderson intends to declare and pay a final cash dividend for the financial year ended December 31, 2016 of 7.30 pence per Henderson ordinary share. The payment of the dividend is subject to approval by Henderson shareholders at the shareholder meeting to be held on April 26, 2017. If approved by Henderson shareholders, such dividend will be paid on or around May 19, 2017.

        Janus has declared and paid to Janus stockholders quarterly cash dividends of US$0.11 and US$0.11 per share of Janus common stock for the third and fourth quarter of 2016 respectively.

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        In addition, each of the Henderson and Janus boards of directors also currently intends to declare and pay to Henderson shareholders or Janus stockholders, as applicable, prior to closing of the merger, an interim dividend in respect of the first quarter of the financial year ending December 31, 2017. The Henderson and Janus boards will determine the amount of any such first quarter 2017 dividend following the end of the first quarter of 2017. Janus Henderson is expected to continue to follow a progressive dividend policy, increasing the dividend broadly in-line with growth in adjusted operating income over the medium term and with a pay-out ratio consistent with Henderson's past practice. Following the closing of the merger, it is intended that Janus Henderson will declare and pay quarterly dividends beginning in the second quarter of 2017.

        However, the amount of dividends, if any, that are declared or paid to Janus Henderson shareholders in periods after closing of the merger cannot yet be determined and will depend on a number of factors. The Janus Henderson board will have sole discretion to determine whether any interim dividends will be declared, the amount of any such interim dividend, the amount of any final dividend recommended to its shareholders (which may be paid subject to the approval of Janus Henderson shareholders by way of an ordinary resolution) and when any dividend will be paid. We expect that such determination would be based on a number of considerations, including, but not limited to, Janus Henderson's results of operations, capital management plans, the market price of Janus Henderson ordinary shares, the combined company's access to capital markets, as well as legal requirements, industry practice and other factors deemed relevant by the Janus Henderson board. There can be no assurance that Janus Henderson shareholders will receive or be entitled to dividends commensurate with the historical dividends of Janus or Henderson. For a further discussion of the risks related to the payment of dividends after the merger, see "Risk Factors—Risks Related to the Merger" beginning on page 71.

Litigation Relating to the Transaction (see page 145)

        The merger agreement requires each party to promptly advise the other party of any litigation brought by any stockholder or shareholder of that party, as applicable, against such party or any of their respective directors relating to the merger agreement or any of the transactions contemplated thereby, and will keep the other party reasonably informed regarding any such litigation. Each party will give the other party the opportunity to participate in the defense or settlement of any such litigation by any stockholders or shareholders, and no such settlement will be agreed to without the other party's prior written consent, which consent will not be unreasonably withheld or delayed. For a description of any current litigation related to the merger agreement and the merger, see "The Merger—Litigation Relating to the Transaction" beginning on page 145 of this proxy statement/prospectus.

Comparison of Rights of Holders Janus Henderson Ordinary Shares and Shares of Janus Common Stock (see page 274)

        Upon closing of the merger, Janus stockholders will become shareholders of Janus Henderson and their rights will be governed by the laws of Jersey, Channel Islands, and the governing documents of Janus Henderson in effect at the effective time, including the Janus Henderson Amended Memorandum and the Janus Henderson Amended Articles. Janus stockholders will have different rights once they become Janus Henderson shareholders due to differences between the governing documents of each of the entities. These differences are described in detail in the section entitled "Comparison of Rights of Holders Janus Henderson Ordinary Shares and Shares of Janus Common Stock" beginning on page 274.

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Jersey Company Considerations (see page 218)

        Henderson's corporate affairs are governed by its existing Memorandum of Association, which we refer to as the Henderson Memorandum of Association, and Articles of Association, which we refer to as the Henderson Articles of Association, and by the laws of Jersey, Channel Islands. Upon consummation of the merger, the rights of Janus Henderson shareholders will be governed by the Janus Henderson Amended Memorandum and the Janus Henderson Amended Articles and the laws of Jersey, Channel Islands. The provisions of the Jersey Companies Law, which applies to Henderson and will apply to Janus Henderson, differ in certain material respects from laws generally applicable to U.S. companies incorporated in the State of Delaware, including Janus, and their stockholders. For additional information, see the section entitled "Comparison of Rights of Holders Janus Henderson Ordinary Shares and Shares of Janus Common Stock" beginning on page 274.

The Special Meeting

The Janus Special Meeting (see page 82)

        Date, Time and Place:    The Janus special meeting will be held at JW Marriott Hotel, 150 Clayton Lane, Denver, Colorado, on April 25, 2017, at 10:00 a.m., Mountain Daylight Time.

        Purpose: At the Janus special meeting, Janus stockholders will be asked:

Record Date; Voting Rights

        Only holders of record of shares of Janus common stock at the close of business on March 15, 2017, the record date for voting at the Janus special meeting, which we refer to as the record date, are entitled to vote at the Janus special meeting. On March 15, 2017, 184,297,796 shares of Janus common stock were issued and outstanding.

        You may cast one vote for each share of Janus common stock that you owned as of the close of business on the record date.

        Votes Required.    The votes required for each proposal are as follows:

        Proposal 1: Janus merger proposal.    The votes cast "FOR" this proposal must represent a majority of all outstanding shares of Janus common stock entitled to vote.

        Proposal 2: Janus compensation proposal.    The affirmative vote of a majority of Janus stockholders present, in person or represented by proxy, and entitled to vote at the Janus special meeting is required to approve the Janus compensation proposal.

        Proposals 3 through 7: Amendment proposals.    The affirmative vote of a majority of Janus stockholders present, in person or represented by proxy, and entitled to vote at the Janus special meeting is required to approve each of the amendment proposals.

        Proposal 8: Janus adjournment proposal.    The affirmative vote of a majority of Janus stockholders present, in person or represented by proxy, and entitled to vote at the Janus special meeting is required to approve the Janus adjournment proposal.

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        Under the NYSE rules, if you hold your shares of Janus common stock in "street name," your broker, nominee or intermediary may not vote your shares without instructions from you on non-routine matters. None of the proposals to be voted on at the Janus special meeting are routine matters. Therefore, without your voting instructions, your broker or other nominee may not vote your shares on any of Proposals 1 through 7 at the Janus special meeting.

        Broker non-votes will have the same effect as a vote "AGAINST" Proposal 1 and will have no effect on Proposals 2 through 7 (assuming a quorum is present). However, because none of the proposals to be voted on at the Janus special meeting are routine matters for which brokers may have discretionary authority to vote, Janus does not expect any broker non-votes at the Janus special meeting.

        As of the close of business on March 15, 2017, 2.23% of the outstanding shares of Janus common stock were held by Janus directors and executive officers and their affiliates. We currently expect that Janus directors and executive officers will vote their shares of Janus common stock in favor of the above-listed proposals, although none of them has entered into any agreements obligating him or her to do so. As of March 15, 19.74% of the outstanding shares of Janus common stock were held by Dai-ichi. Dai-ichi has entered into a voting agreement with Janus and Henderson obligating it to vote all of its shares of Janus common stock "FOR" the Janus merger proposal.

        Closing of the merger is conditioned on approval by Janus stockholders of the Janus merger proposal.

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Selected Consolidated Financial Information of Janus

        The following table sets forth selected historical consolidated financial information for Janus, which is reported in accordance with U.S. GAAP. The historical consolidated financial information for each of the years in the three-year period ended December 31, 2016 and the selected historical consolidated balance sheet data as of December 31, 2016 and 2015 have been derived from the audited consolidated financial statements of Janus contained in its annual report on Form 10-K filed with the SEC on February 16, 2017, which is incorporated by reference into this proxy statement/prospectus. The selected historical consolidated financial information for each of the years ended December 31, 2013 and 2012 and the selected balance sheet data as of December 31, 2014, 2013, and 2012 have been derived from Janus's audited consolidated financial statements as of and for such years contained in Janus's other reports filed with the SEC, which are not incorporated by reference into this proxy statement/prospectus. The following information should be read together with Janus's consolidated financial statements and the notes related to those financial statements. See "Where You Can Find More Information" beginning on page 300. Janus's historical consolidated financial information may not be indicative of the future performance of Janus or the combined company. All results of operations presented are continuing operations.

 
  Year ended December 31,  
Selected Consolidated Income Statement Data
  2016   2015   2014   2013   2012  
 
  ($ millions unless otherwise stated)
 

Total operating revenue

    1,010.7     1,076.2     953.2     873.9     850.0  

Income before taxes

    242.2     253.3     257.7     195.5     176.6  

Income tax provision

    (90.9 )   (94.0 )   (102.3 )   (73.3 )   (64.7 )

Net income

    151.3     159.3     155.4     122.2     111.9  

Net income attributable to non-controlling interests

    (5.2 )   (3.5 )   (1.0 )   (7.5 )   (9.6 )

Net income attributable to Janus

    146.1     155.8     154.4     114.7     102.3  

Earnings per share attributable to Janus common shareholders

                               

—Basic ($ per share)

    0.79     0.84     0.82     0.62     0.56  

—Diluted ($ per share)

    0.78     0.80     0.81     0.62     0.55  

Dividends per share paid to Janus common shareholders ($ per share)

    0.42     0.35     0.31     0.21     0.29  

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  As of December 31,  
Selected Consolidated Balance Sheet Data
  2016   2015   2014   2013   2012  
($ millions)
   
   
   
   
   
 

Total assets

    2,949.9     2,867.7     2,790.5     2,743.5     2,657.5  

Long-term debt (including current portion)

    406.3     402.3     447.8     540.8     542.2  

Deferred income taxes, net

    502.8     498.9     478.4     447.7     436.0  

Other non-current liabilities

    46.7     46.2     41.2     32.4     41.8  

Total liabilities

    1,187.5     1,173.8     1,197.0     1,225.7     1,179.5  

Net assets

    1,762.4     1,693.9     1,593.5     1,517.8     1,478.0  

Redeemable noncontrolling interests

    43.1     21.8     5.4     7.3     42.9  

Total Janus shareholders' equity

    1,630.4     1,582.7     1,540.8     1,496.8     1,417.9  

Noncontrolling interests

    88.9     89.4     47.3     13.7     17.2  

Total equity

    1,719.3     1,672.1     1,588.1     1,510.5     1,435.1  

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Selected Consolidated Financial Information of Henderson

        The following is a summary of Henderson's selected historical consolidated financial data for the periods ended and as at the dates, and on the basis of accounting, as indicated below. You are encouraged to read this information together with the consolidated financial statements of Henderson and the accompanying notes and the section entitled "Management's Discussion and Analysis of Financial Condition and Results of Operations of Henderson" included elsewhere in this proxy statement/prospectus.

U.S. GAAP Information

        This presentation includes selected historical consolidated financial data as of December 31, 2016 and 2015 and for the years ended December 31, 2016, 2015 and 2014 derived from Henderson's audited consolidated financial statements for those years, prepared in accordance with U.S. GAAP, which are included elsewhere in this proxy statement/prospectus.

IFRS Information

        This presentation includes selected historical consolidated financial data for the years ended December 31, 2016, 2015, 2014, 2013 and 2012 derived from Henderson's audited consolidated financial statements for those years, prepared in accordance with IFRS, which are not included elsewhere in this proxy statement/prospectus.

        For additional information, see Henderson's consolidated financial statements and the accompanying notes included in this proxy statement/prospectus.

Prepared in Accordance with U.S. GAAP

 
  Year ended December 31,  
Selected Consolidated Income Statement Data
  2016   2015   2014  
 
  ($ millions unless otherwise stated)
 

Total revenue

    999.9     1,155.1     1,105.7  

Income before taxes

    211.9     337.5     563.6  

Income tax provision

    (34.6 )   (6.1 )   (52.6 )

Net income

    177.3     331.4     511.0  

Basic and diluted earnings per share from total operations

                   

—Basic ($ per share)

    0.17     0.29     0.45  

—Diluted ($ per share)

    0.17     0.28     0.42  

Dividends per share paid to equity shareholders (£ per share)

    0.105     0.103     0.090  

 

 
  As at December 31,  
Selected Consolidated Balance Sheet Data
  2016   2015  
 
  ($ millions)
 

Non-current assets

    1,372.7     1,600.4  

Total current assets

    1,060.7     1,234.8  

Total assets

    2,433.4     2,835.2  

Total current liabilities

    452.8     682.1  

Non-current liabilities

    130.3     159.2  

Total liabilities

    583.1     841.3  

Share capital

    234.4     234.4  

Total shareholders' equity

    1,647.5     1,866.9  

Non-controlling interests

    44.8     44.1  

Total equity

    1,692.3     1,911.0  

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Prepared in Accordance with IFRS

 
  Year ended December 31,  
Selected Consolidated Income Statement Data
  2016   2015   2014   2013   2012  
 
  (£ millions unless otherwise stated)
 

Gross fee and deferred income

    738.0     756.0     651.2     578.2     656.9  

Net fee income

    583.7     601.8     518.8     461.3     371.5  

Profit /(loss) before tax from continuing operations

    139.2     167.9     135.6     107.3     76.3  

Profit /(loss) after tax from continuing operations

    109.6     161.2     126.9     107.2     84.2  

Profit /(loss) before tax from total operations

    139.2     167.9     283.4     127.4     102.7  

Tax (charge)/credit on total operations

    (29.6 )   (6.7 )   (24.9 )   (2.3 )   3.7  

Profit /(loss) after tax attributable to owners of the parent

    109.6     161.2     258.5     125.1     106.4  

Basic and diluted earnings per share from continuing operations

                               

—Basic (£ per share)

    0.10     0.147     0.117     0.101     0.081  

—Diluted (£ per share)

    0.098     0.141     0.111     0.094     0.078  

Basic and diluted earnings per share from total operations

                               

—Basic (£ per share)

    0.10     0.147     0.238     0.118     0.103  

—Diluted (£ per share)

    0.098     0.141     0.227     0.110     0.098  

Dividends per share paid to equity shareholders (£ per share)

    0.104     0.095     0.0845     0.072     0.0715  

 

 
  As at December 31,  
Selected Consolidated Balance Sheet Data
  2016   2015   2014   2013   2012  
 
  (£ millions)
 

Non-current assets

    838.9     865.5     932.8     841.1     944.2  

Current assets

    777.3     825.5     619.6     517.6     427.8  

Total assets

    1,616.2     1,691.0     1,637.2     1,464.5     1,372.0  

Current liabilities

    449.3     560.3     342.1     354.7     318.3  

Non-current liabilities

    85.0     83.0     251.1     267.9     272.0  

Total liabilities

    534.3     643.3     619.2     628.2     590.3  

Share capital

    141.5     141.5     142.4     140.4     139.3  

Equity attributable to equity holder of the parent

    1,064.9     1,037.1     1,016.1     832.2     777.6  

Non-controlling interests

    17.0     10.6     1.9     4.0     4.1  

Total equity

    1,081.9     1,047.7     1,018.0     836.3     781.7  

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Summary Unaudited Pro Forma Condensed Combined Financial Information

        The following table shows summary unaudited pro forma condensed combined financial information, which Janus and Henderson refer to as the summary pro forma financial information, about the financial condition and results of operations of the combined company, after giving effect to the merger, which were prepared using the acquisition method of accounting with Henderson designated as the accounting acquirer of Janus. See "The Merger—Accounting Treatment" beginning on page 142 and see "Unaudited Pro Forma Condensed Combined Financial Information" beginning on page 259 for more information.

        The summary pro forma financial information is presented for illustrative purposes only and is not necessarily indicative of the unaudited operating results or financial position that would have occurred if the merger had been completed as of the beginning of the period presented, nor is it necessarily indicative of the future operating results or financial position of the combined company. In addition, the summary pro forma financial information includes adjustments which are preliminary and may be revised. There can be no assurance that such revisions will not result in material changes to the information presented. The summary pro forma financial information does not include estimated cost or growth synergies, adjustments related to restructuring or integration activities, future acquisitions or disposals not yet known or probable, including those that may be required by regulatory or governmental authorities in connection with the merger, or impacts of merger related change in control provisions that are currently not factually supportable and/or probable of occurring.

Income Statement Data
($ in millions, except per share data)
  For the fiscal year
ended
December 31, 2016
 

Revenues:

       

Management fees

  $ 1,746.0  

Performance fees

    18.2  

Other revenue

    246.4  

Total revenue

  $ 2,010.6  

Operating expenses:

       

Employee compensation and benefits

    631.2  

Long-term incentive compensation

    166.4  

Distribution expenses

    337.3  

Amortization and depreciation

    71.7  

Investment administration

    55.5  

General, administrative and occupancy

    253.7  

Total operating expenses

  $ 1,515.8  

Operating income

  $ 494.8  

Interest expense

    (22.2 )

Investment gain/(losses), net

    (6.3 )

Other non-operating income, net

    2.0  

Income before taxes

    468.3  

Income tax provision

    (125.1 )

Net income

    343.2  

Non-controlling interests

    6.5  

Net income attributable to parent

  $ 349.7  

Earnings per share attributable to common shareholders

       

Basic

    1.77  

Diluted

    1.73  

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Balance Sheet Data
($ in millions)
  As of
December 31,
2016
 

ASSETS

       

Current assets:

       

Cash and cash equivalents

    743.8  

Investment securities

    291.7  

Accrued income and accounts receivable

    295.1  

OEIC and unit trust debtors

    142.1  

Assets of consolidated VIEs:

       

Cash and cash equivalents

    50.3  

Investment securities

    405.3  

Other current assets

    8.4  

Other current assets

    104.0  

Total current assets

    2,040.7  

Non-current assets:

       

Property and equipment, net

    85.4  

Intangible assets, net

    3,227.3  

Goodwill

    1,134.7  

Retirement benefit asset, net

    180.2  

Other non-current assets

    22.2  

Total non-current assets

    4,649.8  

Total assets

  $ 6,690.5  

LIABILITIES AND EQUITY

       

Current liabilities:

       

Other accrued liabilities

    314.5  

Current portion of accrued compensation, benefits and staff costs

    338.8  

OEIC and unit trust payables

    137.9  

Liabilities of consolidated VIEs:

       

Other current liabilities

    26.7  

Other current liabilities

    109.6  

Total current liabilities

  $ 927.5  

Non-current liabilities:

       

Deferred tax liabilities, net

    948.4  

Retirement benefit obligations, net

    11.9  

Accrued compensation, benefits and staff costs

    8.7  

Long term debt

    426.5  

Other non-current liabilities

    85.7  

Total non-current liabilities

  $ 1,481.2  

Total liabilities

  $ 2,408.7  

Redeemable non-controlling interests

 
$

201.1
 

Equity:

       

Common stock

    367.8  

Additional paid in capital

    3,535.5  

Treasury shares

    (155.1 )

Accumulated other comprehensive income, net of tax

    (434.5 )

Retained earnings

    596.7  

Total shareholders' equity

  $ 3,910.4  

Non-controlling interests

  $ 170.3  

Total equity

  $ 4,080.7  

Total liabilities, redeemable non-controlling interests and equity

  $ 6,690.5  

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COMPARATIVE HISTORICAL AND PRO FORMA PER SHARE INFORMATION

        The following table summarizes unaudited per share information for Henderson and Janus on a historical basis and unaudited pro forma combined basis for Henderson and Janus reflecting the merger and related transactions and adjustments. The following information should be read in conjunction with the audited consolidated financial statements and accompanying notes of Henderson and Janus, and the unaudited pro forma condensed combined financial statements beginning on page 259. The unaudited pro forma information is presented for illustrative purposes only and is not necessarily indicative of what the operating results or financial position would have been if the merger had been completed as of the beginning of the period presented, nor is it necessarily indicative of the future operating results or financial position of the combined companies. The historical earnings per share, dividends per share and book value per share of Henderson and Janus shown in the table below are derived from their audited consolidated financial statements as of and for the years ended December 31, 2016.

        The historical book value per share is computed by dividing total shareholders' equity by the number of shares outstanding at the end of the period, excluding any shares held in treasury. The unaudited pro forma combined earnings per share from continuing operations is computed by dividing the pro forma earnings from continuing operations available to holders of shares by the pro forma weighted-average number of shares outstanding of Henderson plus the actual number of shares outstanding for Janus multiplied by the exchange ratio. The unaudited pro forma combined book value per share is computed by dividing total pro forma shareholders' equity by the pro forma number of shares outstanding at the end of the period. Pro forma per share information is presented as if the merger and related transactions and adjustments occurred as of the date of the historical financial statements.

 
  As of or for the
fiscal year ended
December 31,
2016
 

Henderson—Historical

       

Historical per Henderson ordinary share:

       

Diluted earnings per share

  $ 0.17  

Cash dividends declared per share(1)

  £ 0.104  

Book value per share

  $ 1.51  

Janus—Historical

   
 
 

Historical per Janus share of common stock:

       

Diluted earnings per share

  $ 0.78  

Cash dividends declared per share(2)

  $ 0.42  

Book value per share

  $ 9.412  

Unaudited Pro Forma Combined

   
 
 

Diluted earnings per share

  $ 1.73  

Cash dividends declared per share(3)

  $ 0.1423  

Book value per share

  $ 20.6  

(1)
On February 8, 2017, the Henderson board declared a final dividend of £0.073 per share which, subject to shareholder approval, will be paid on May 19, 2017. This amount has not been included in the table above.

(2)
On January 19, 2017, the Janus board declared a dividend of $0.11 per share, which was paid on February 17, 2017. This amount has not been included in the table above.

(3)
Henderson historical data translated at £ / $ average rate for the period.

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COMPARATIVE PER SHARE MARKET PRICE AND DIVIDEND INFORMATION

        Henderson ordinary shares are listed on the LSE under the symbol "HGG". Janus shares of common stock are listed on the NYSE under the symbol "JNS". The table below sets forth, for the periods indicated, the high and low closing prices per share reported on the LSE and on the NYSE, as applicable.

 
  Henderson
Ordinary
Shares (£)
  Janus Common
Stock ($)
 
 
  High   Low   High   Low  

2017

                         

March (through March 17)

    2.315     2.236     12.96     12.33  

February

    2.291     2.118     12.79     12.08  

January

    2.446     2.166     13.72     12.35  

First Quarter (through March 17)

    2.446     2.118     13.72     12.08  

2016

   
 
   
 
   
 
   
 
 

December

    2.374     2.284     14.25     13.27  

November

    2.455     2.185     14.18     12.36  

October

    2.707     2.315     15.70     12.65  

September

    2.452     2.286     14.78     13.78  

August

    2.538     2.3     15.00     14.54  

Fourth Quarter

    2.707     2.185     16.01     11.97  

Third Quarter

    2.538     1.981     15.1     13.63  

Second Quarter

    2.692     2.185     15.71     13.14  

First Quarter

    3.008     2.146     14.69     11.47  

2015

   
 
   
 
   
 
   
 
 

Fourth Quarter

    3.12     2.575     16.01     13.37  

Third Quarter

    2.941     2.418     17.29     13.29  

Second Quarter

    3.016     2.61     18.75     16.66  

First Quarter

    2.929     2.063     18.59     15.56  

2014

   
2.703
   
1.846
   
16.47
   
10.32
 

2013

    2.286     1.323     12.50     8.09  

2012

    1.327     0.9055     9.55     6.60  

        The table below sets forth, for the periods indicated, the dividends declared on Henderson ordinary shares and on shares of Janus common stock. Henderson interim dividends are declared in the third quarter of the relevant financial year, whereas the final dividend is declared in the second quarter of the following financial year to which the dividend relates (and is paid after the final dividend is approved at the company's annual general meeting, generally held in the second quarter of that following financial year). Henderson declared a final dividend of £0.073 per share which, subject to

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shareholder approval, will be paid on May 19, 2017. This amount has not been included in the table below.

 
  Henderson
Ordinary
Shares (£)
  Janus
Common
Stock ($)
 
 
  Dividend   Dividend  

2017

             

First Quarter

        0.11  

2016

   
 
   
 
 

Fourth Quarter

        0.11  

Third Quarter

    0.032     0.11  

Second Quarter

    0.072     0.11  

First Quarter

        0.09  

2015

   
 
   
 
 

Fourth Quarter

        0.09  

Third Quarter

    0.031     0.09  

Second Quarter

    0.064     0.09  

First Quarter

        0.08  

2014

   
 
   
 
 

Fourth Quarter

        0.08  

Third Quarter

    0.026     0.08  

Second Quarter

    0.0585     0.08  

First Quarter

        0.07  

        The following table presents trading information for Henderson ordinary shares on the LSE and for shares of Janus common stock on the NYSE on (1) September 30, 2016, the last trading day before the date of public announcement of the execution of the merger agreement, and (2) March 17, 2017, the latest practicable trading date before the date of this proxy statement/prospectus.

 
  Henderson Ordinary Shares
(pence)
  Janus Common Stock
($)
 
 
  High   Low   Close   High   Low   Close  

September 30, 2016

    233.70     224.30     232.00     14.09     13.82     14.01  

March 17, 2017

    234.50     230.10     231.00     13.01     12.78     12.82  

        The value of the Henderson ordinary shares to be issued as consideration in the merger will change as the market price of Henderson ordinary shares fluctuates, and therefore will likely be different from the prices set forth above at the time you receive your Henderson ordinary shares. See the section in this proxy statement/prospectus titled "Risk Factors—Risks Related to the Merger—Janus Stockholders cannot be sure of the value of the merger consideration they will receive."

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EXCHANGE RATE INFORMATION

        For your convenience, this proxy statement/prospectus contains translations of pounds sterling amounts into U.S. dollars. These translations have been made at the spot rate for the specified day as reported from Reuters. These translations have been provided solely for your convenience and are not representations that the pounds sterling amounts actually represent these U.S. dollar amounts or could be converted to U.S. dollars at the rates indicated.

        The exchange rate for pounds sterling on March 17, 2017, the latest practicable date before the date of this proxy statement/prospectus, was $1.2376 per pound sterling as reported from Reuters.

        The following tables set forth, for the periods indicated, information concerning the exchange rate, expressed in U.S. dollars per pound sterling as reported by Bloomberg.

 
  Average Rate
for the
Period(1)
 

Annual data (Year ended December 31)

       

2012

    1.58984  

2013

    1.57075  

2014

    1.647215  

2015

    1.527946  

2016

    1.35486  

2017 (through March 17)

    1.237545  

Note:

(1)
The average of the exchange rate on the last business day of each month during the period.
 
  High   Low  

Monthly data

             

August 2016

    1.3325     1.28775  

September 2016

    1.343     1.2952  

October 2016

    1.2873     1.2131  

November 2016

    1.2587     1.22195  

December 2016

    1.2711     1.22275  

January 2017

    1.2614     1.20645  

February 2017

    1.26465     1.24305  

March 2017 (through March 17)

    1.23760     1.21505  

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

        This proxy statement/prospectus contains "forward-looking statements." In this context, forward-looking statements often address expected future business and financial performance and financial condition, and often contain words such as "expect," "anticipate," "intend," "plan," "believe," "seek," "see," "will," "would," "target," similar expressions, and variations or negatives of these words. Forward-looking statements by their nature address matters that are, to different degrees, uncertain, such as statements about consummation of the merger and the anticipated benefits thereof. These and other forward-looking statements, including the failure to consummate the merger or to make or take any filing or other action required to consummate such transaction in a timely matter or at all, are not guarantees of future results and are subject to numerous risks, uncertainties and assumptions that could cause actual results to differ materially from those expressed in any forward-looking statements. Important risk factors that may cause such a difference include, but are not limited to, (i) the closing of the merger on anticipated terms and timing, including obtaining required shareholder approvals, anticipated tax treatment, unforeseen liabilities, failure to obtain board and shareholder approval from the Janus U.S. mutual funds for new investment advisory agreements, failure to obtain regulatory approvals and other conditions to the closing of the merger, (ii) risks related to the operation of the combined business, including macro-economic conditions, investment performance, operation of an international business, exchange rate fluctuations, failure or breach of security systems, indebtedness, continued availability of capital and financing and rating agency actions, managing expenses, operational losses, future prospects and business and management strategies for the management, expansion and growth of the combined company's operations, (iii) the ability of Janus and Henderson to integrate their businesses successfully and to achieve anticipated synergies, (iv) potential litigation relating to the merger, (v) the risk that disruptions from the merger will harm Janus's or Henderson's business, including current plans and operations, (vi) the ability of Janus or Henderson to retain and hire key personnel, (vii) potential adverse reactions or changes to business relationships resulting from the announcement or closing of the merger, (viii) termination of existing investment advisory agreements, (ix) political, legislative, regulatory and economic developments, (x) potential business uncertainty, including changes to existing business relationships, during the period before closing of the merger that could affect Janus's and/or Henderson's financial performance, (xi) certain restrictions during the period before closing of the merger that may impact Janus's or Henderson's ability to pursue certain business opportunities or strategic transactions and (xii) unpredictability and severity of catastrophic events, including, but not limited to, acts of terrorism or outbreak of war or hostilities, as well as management's response to any of the aforementioned factors. Consequences of material differences in results as compared with those anticipated in the forward-looking statements could include, among other things, business disruption, operational problems, financial loss, legal liability to third parties and similar risks, any of which could have a material adverse effect on Janus's or Henderson's assets under management, consolidated financial condition, results of operations or liquidity. The information contained herein speaks as of the date hereof. Neither Janus nor Henderson assumes any obligation to publicly provide revisions or updates to any forward looking statements, whether as a result of new information, future developments or otherwise, should circumstances change, except as otherwise required by securities and other applicable laws. Because forward-looking statements are subject to assumptions and uncertainties, actual results or future events could differ, possibly materially, from those that Janus or Henderson anticipated in its forward-looking statements and future results could differ materially from historical performance. Factors that could cause or contribute to such differences include, but are not limited to, those included under "Risk Factors" starting on page 50.

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RISK FACTORS

Risks Related to the Combined Business of Janus and Henderson

Janus's and Henderson's results of operations and financial condition are, and the combined company's results of operations and financial condition will be, primarily dependent on the value, composition and relative investment performance of their collective investment products.

        Any decrease in the value, relative investment performance or amount of assets under management will cause a decline in revenue and negatively impact operating results and the financial condition of Janus Henderson. Assets under management may decline for various reasons, many of which will not be under the control of Janus Henderson.

        Factors that could cause assets under management and revenue to decline include the following:

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Janus Henderson may fail to successfully implement a strategy for the combined business, which could negatively impact the combined company's assets under management, results of operations and financial condition.

        Through the combination of Janus and Henderson, the combined company intends to establish an independent, active asset manager with a globally relevant brand, footprint, investment proposition and client service. No assurance can be given that the combined company will successfully achieve this objective or that this objective will lead to increased revenue and net income, or to the creation of shareholder value. The failure to successfully implement a strategy for Janus Henderson could adversely affect the combined company's assets under management, results of operations and financial condition.

Janus Henderson's revenue and profitability would be adversely affected by any reduction in assets under management as a result of redemptions and other withdrawals from the funds and accounts managed.

        Redemptions or withdrawals may be caused by investors (in response to adverse market conditions or pursuit of other investment opportunities or as a consequence of damage to Janus Henderson's reputation, among other factors) reducing their investments in funds and accounts in general or in the market segments on which Janus Henderson focuses; investors taking profits from their investments; poor investment performance of the funds and accounts managed by Janus Henderson; and portfolio risk characteristics, which could cause investors to move assets to other investment managers. Poor performance relative to competing products provided by other investment management firms tends to result in decreased sales, increased redemptions of fund shares and the loss of or reduction in assets under management in private institutional accounts, with corresponding decreases in revenue. Failure of the Janus Henderson funds and accounts to perform well could, therefore, have a material adverse effect on the results of operations and financial condition of the combined company.

Janus Henderson will operate in a highly competitive environment and revenue from fees may be reduced.

        The investment management business is highly competitive and has relatively low barriers to entry. In addition, established firms as well as new entrants to the asset management industry have, in recent years, expanded their application of technology, including through the use of robo-advisers, in providing services to clients. Janus's and Henderson's traditional fee structures may be subject to downward pressure due to these factors. Moreover, in recent years there has been a trend toward lower fees in the investment management industry, as evidenced by the movement toward passively managed mutual funds and the growth of lower cost funds such as exchange traded, smart beta and quant funds. Fees for actively managed investment products may come under increased pressure if such products fail to outperform returns for comparable passively managed products or as a consequence of regulatory intervention. Fee reductions on existing or future new business as well as changes in regulations pertaining to fees could adversely affect the combined company's results of operations and financial condition. Additionally, Janus Henderson will compete with investment management companies on the basis of investment performance, fees, diversity of products, distribution capability, reputation and the ability to develop new investment products to meet the changing needs of investors. Failure to adequately compete could adversely affect the combined company's assets under management, results of operations and financial condition.

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The combined company's results will be dependent on its ability to attract and retain key personnel.

        The investment management business is highly dependent on the ability to attract, retain and motivate highly skilled and often highly specialized technical, executive, sales and investment management personnel. The market for qualified investment and sales professionals is extremely competitive and is characterized by the frequent movement of portfolio managers, analysts and salespeople among different firms. Any changes to management structure, shifts in corporate culture, changes to corporate governance authority, or adjustments or reductions to compensation, any of which may occur as a result of the merger, could affect the combined company's ability to retain key personnel and could result in legal claims. If Janus Henderson is unable to retain key personnel, particularly those personnel responsible for managing client funds that account for a high proportion of Janus Henderson's revenue, it could adversely affect the combined company's assets under management, results of operations and financial condition.

The combined company will be dependent upon third-party distribution channels to access clients and potential clients.

        Janus Henderson's ability to market and distribute its investment products is significantly dependent on access to the client base of insurance companies, defined contribution plan administrators, securities firms, broker-dealers, financial advisors, multi-managers, banks and other distribution channels. These companies generally offer their clients various investment products in addition to, and competitive with, products offered by Janus and Henderson. Further, Janus's separate account business uses referrals from financial planners, investment advisers and other professionals. Janus and Henderson cannot be certain that the combined company will continue to have access to these third-party distribution channels or have an opportunity to offer some or all of its investment products through these channels. In addition, Janus's and Henderson's existing relationships with third-party distributors and access to new distributors could be adversely affected by recent consolidation within the financial services industry. Consolidation may result in increased distribution costs, a reduction in the number of third parties distributing Janus's and Henderson's investment products or increased competition to access third-party distribution channels. The inability to access clients through third-party distribution channels could adversely affect the combined company's business prospects, assets under management, results of operations and financial condition.

Illiquidity in certain securities in which Janus Henderson invests may negatively impact the financial condition of the combined company's investment products, and may impede the ability of Janus Henderson funds to effect redemptions.

        Janus Henderson is exposed to the risk that some of its funds or mandates invest in certain securities or other assets in which the secondary trading market is illiquid or in which there is no secondary trading market at all. Illiquidity may occur with respect to the securities of a specific issuer, of issuers within a specific industry or sector, of issuers within a specific geographic region or regions, with respect to an asset class or an investment type, or with respect to the market as a whole. An illiquid trading market may increase market volatility and may make it impossible for funds or mandates to sell investments promptly without suffering a loss. This may have an adverse impact on the investment performance of such funds and mandates and on the assets under management, revenues and results of operations of Janus Henderson.

        Investors in certain funds managed by Janus Henderson have contractual terms that provide for a shorter notice period than the time period during which these funds may be able to sell underlying investments within the fund. This liquidity mismatch may be exacerbated during periods of market illiquidity and, in circumstances in which there are high levels of investor redemptions, it may be necessary for Janus Henderson to impose "gates" on redeeming investors, suspend redemptions or

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create "sidepockets". Such actions may increase the risk of legal claims by investors, regulatory investigation and/or fines and adversely affect the reputation of Janus Henderson.

INTECH's investment process is highly dependent on key employees and proprietary software.

        INTECH's investment process (which relates to approximately 24% of Janus's assets under management as of December 31, 2016) is based on complex and proprietary mathematical models that seek to outperform various indices by capitalizing on the volatility in stock price movements while controlling trading costs and overall risk relative to the index. The maintenance of such models for current products and the development of new products is highly dependent on certain key INTECH employees. If INTECH is unable to retain key personnel or properly transition key personnel responsibilities to others, if the mathematical investment strategies developed by INTECH fail to produce the intended results, or if errors occur in the development or implementation of INTECH's mathematical models, INTECH may not be able to maintain its historical level of investment performance, which could adversely affect Janus Henderson's assets under management, results of operations and financial condition and could also result in legal claims against Janus Henderson or regulatory investigations in respect of its operations.

Changes in the value of seeded investment products could affect Janus Henderson's non-operating income or earnings and could increase the volatility of its earnings.

        Janus and Henderson periodically add new investment strategies to their respective investment product offerings and provide the initial cash investment or "seeding" to facilitate the launch of the product. Janus or Henderson may also provide substantial supplemental capital to an existing investment product in order to accelerate the growth of a strategy and attract outside investment in the product. A decline in the valuation of these seeded investments could negatively impact Janus Henderson's earnings and financial condition.

The global scope of Janus Henderson's business will subject the combined company to exchange rate risk that may adversely impact the combined company's revenue and income.

        Henderson generates, and, following consummation of the merger, Janus Henderson will generate, a substantial portion of its revenue in pounds sterling, euro and Australian dollars. As a result, Janus Henderson will be subject to foreign currency exchange risk relative to the U.S. dollar, Janus Henderson's financial reporting currency, through its non-U.S. operations. Fluctuations in the exchange rates to the U.S. dollar may affect Janus Henderson's financial results from one period to the next. In addition, the combined company will have risk associated with the foreign exchange revaluation of balances held by certain subsidiaries for which the local currency is different than the combined company's functional currency.

The global scope of Janus Henderson's business will subject the combined company to market-specific political, economic and other risks that may adversely impact the combined company's revenue and income generated overseas.

        The combined company's global portfolios and revenue derived from managing these portfolios will be subject to significant risks of loss as a result of political, economic, and diplomatic developments, currency fluctuations, social instability, changes in governmental policies, expropriation, nationalization, asset confiscation and changes in legislation related to non-U.S. ownership. Political events in any country or region could result in significant declines in equity and/or fixed income securities exposed to such a country or region and, to the extent that Janus Henderson has a concentration of assets under management in such a country or region could result in a material adverse effect on the assets under management, results of operations and financial condition of the combined company. In addition, international trading markets, particularly in some emerging market

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countries, are often smaller, less liquid, less regulated and significantly more volatile than those in the U.S. As the combined company's business grows in non-U.S. markets, any ongoing and future business, political, economic or social unrest affecting these markets may have a negative impact on the long-term investment climate in these and other areas and, as a result, on Janus Henderson's assets under management and the corresponding revenue and income generated from these markets may be negatively affected.

Janus Henderson will operate in an industry that is highly regulated in many countries, and any enforcement action or adverse changes in the laws or regulations governing its business could adversely affect its results of operations or financial condition.

        Like all investment management firms, Janus Henderson's activities will be highly regulated in almost all countries in which it conducts business. The combined company will be subject to regulation in the U.S., the U.K., Europe, Australia and in other international markets, including regulation by the SEC, FINRA, the Commodities Future Trading Commission, which we refer to as the CFTC, the National Futures Association, which we refer to as the NFA, the Australian Securities and Investments Commission in Australia, and the FCA in the U.K. Subsidiaries operating in the European Union, which we refer to as the EU, are subject to various EU Directives, which are implemented by member state national legislation. Janus Henderson's operations elsewhere in the world are regulated by similar regulatory organizations. See the section entitled "Business of Henderson—Regulation" in this proxy statement/prospectus and the section entitled "Business—Regulation," in Janus's Annual Report on Form 10-K for the fiscal year end December 31, 2016, incorporated by reference herein.

        Laws and regulations applied at the national, state or provincial and local level generally grant governmental agencies and industry self-regulatory authorities broad administrative discretion over Janus Henderson's activities, including the power to limit or restrict its business activities, conduct examinations, risk assessments, investigations and capital adequacy reviews, and impose remedial programs to address perceived deficiencies. As a result of regulatory oversight, Janus Henderson could face requirements which negatively impact the way in which it conducts business, increase compliance costs, impose additional capital requirements and/or involve enforcement actions which could lead to sanctions up to and including the revocation of licenses to operate certain businesses, the suspension or expulsion from a particular jurisdiction or market of any of its business organizations or key personnel, or the imposition of fines and censures on it or its employees. Judgments or findings of wrongdoing by regulatory or governmental authorities, or in private litigation against Janus Henderson, could affect its reputation, increase its costs of doing business and/or negatively impact revenues, any of which could have an adverse impact on Janus Henderson's results of operations or financial condition.

        Janus Henderson may also be adversely affected as a result of new or revised legislation or regulations, or by changes in the interpretation or enforcement of existing laws and regulations. The costs and burdens of compliance with these and other current and future reporting and operational requirements and regulations have increased significantly and may continue to increase the cost of offering mutual funds and other investment products, which could adversely affect Janus Henderson's assets under management, results of operations and financial condition.

        The regulatory environment in which Janus Henderson operates frequently changes and has seen a significant increase in regulation in recent years. Various changes in laws and regulations have been enacted or otherwise developed in multiple jurisdictions globally in response to the crisis in the financial markets that began in 2007. Various other proposals remain under consideration by legislators, regulators, and other government officials and other public policy commentators. Certain enacted provisions and certain other proposals are potentially far reaching and, depending upon their implementation, could have a material impact on Janus Henderson's business. While certain of these provisions appear to address perceived problems in the banking sector, some will or may be applied more broadly and affect other financial services companies, including investment managers. Janus

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Henderson may be adversely affected as a result of the new or revised legislation or regulations or by changes in the interpretation or enforcement of existing laws and regulations.

Proposed Changes in the U.S. Regulatory Framework

        In the U.S., the Dodd-Frank Wall Street Reform and Consumer Protection Act, which we refer to as the Dodd-Frank Act, was signed into law in July 2010. Certain provisions have required Janus and/or Henderson, and other provisions will or may require Janus Henderson, to change or impose new limitations on the manner in which it conducts business; they also have increased regulatory burdens and related compliance costs, and will or may continue to do so. Moreover, the Dodd-Frank Act mandated many regulatory studies, some of which pertain directly to the investment management industry, which could lead to additional legislation or regulation.

        In December 2014, the Chairperson of the SEC announced a comprehensive agenda for regulatory change governing the U.S. asset management industry and directed SEC staff to develop a five-part series of new regulations addressing the topics of enhanced portfolio reporting, liquidity risk management, leverage and use of derivatives, adviser wind up and stress testing for funds and advisers. When finalized, these new industry rules can be expected to add additional reporting and compliance costs and may affect the development of new products. Janus Henderson believes these proposals could increase operational and compliance costs.

        The U.S. Department of Labor has adopted regulations that are currently scheduled to go into effect on April 10, 2017, that will treat as fiduciaries any person who provides investment advice or recommendations to employee benefit plans, plan fiduciaries, plan participants, plan beneficiaries, Individual Retirement Accounts, which we refer to as IRAs, or IRA owners. The proposal will have wide-ranging consequences for Janus Henderson and its U.S. distribution partners and product line. Under the new rules, firms and individuals who recommend financial products to retirement investors would be required to act in the best interest of the investor and, to receive variable compensation, would be required to enter into a contract with clients and produce complex disclosure documents intended to highlight financial conflicts of interest that may arise from the compensation the financial adviser receives from firms like Janus Henderson.

        With the commencement of President Trump's new administration, the regulatory moratorium imposed by President Trump on January 20, 2017, the possibility for the repeal of aspects of the Dodd-Frank Act, delay of the U.S. Department of Labor's fiduciary rule and other deregulation, and other political uncertainty in the U.S. following the 2016 Presidential and Congressional elections, the regulatory environment in the U.S. may experience increased volatility. At this time, it is not possible to determine the impact such reforms would have on Janus Henderson's business.

Proposed Changes in the European Union Regulatory Framework

        The European Union has promulgated or is considering various new or revised directives pertaining to financial services, including investment managers. Such directives are progressing at various stages, and have been, are being, or will or would be implemented by national legislation in member states. The Alternative Investment Fund Manager Directive, which we refer to as AIFMD, is an example of such regulation, as is the Markets in Financial Instruments Directive II, which we refer to as MiFID II, which seeks to promote a single market for wholesale and retail transactions in financial instruments. MiFID II addresses the conduct of business rules for intermediaries providing investment services and the effective, efficient and safe operation of financial markets. Key elements of MiFID II in relation to investor protection measures include changes to the extent to which retrocessions may be paid and the use of trading commissions to fund research.

        Implementing legislation in member states has, among other elements, imposed restrictions on the marketing and sale within the EU of private equity and other alternative investment funds sponsored

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by non-EU managers. Various regulators promulgated or are considering other new disclosure or suitability requirements pertaining to the distribution of investment funds and other investment products, including enhanced standards and requirements pertaining to disclosures made to retail investors at the point of sale. As with the Dodd-Frank Act, Janus and Henderson do not believe implementation of these directives will fundamentally change the asset management industry or cause Janus Henderson to reconsider its fundamental strategy, but certain provisions have required Janus and/or Henderson, and other provisions will or may require Janus Henderson, to change or impose new limitations on the manner in which it conducts business; they also have increased regulatory burdens and compliance costs, and will or may continue to do so. Certain provisions may have unintended adverse consequences on the liquidity or structure of the financial markets. Similar developments are being implemented or considered in other jurisdictions where Janus Henderson does business; such developments could have similar effects.

        The full impact of potential legal and regulatory changes or possible enforcement proceedings on the Janus Henderson business cannot be predicted. Such changes have imposed, and may continue to impose, new compliance costs and/or capital requirements, including costs related to information technology systems, or may impact Janus Henderson in other ways that could have an adverse impact on Janus Henderson's results of operations or financial condition. Similarly, regulatory enforcement actions which impose significant penalties or compliance obligations or which result in significant reputational harm could have similar adverse effects on Janus Henderson. Moreover, certain legal or regulatory changes could require Janus Henderson to modify its strategies, businesses or operations, and it may incur other new constraints or costs, including the investment of significant management time and resources in order to satisfy new regulatory requirements or to compete in a changed business environment. In recent years, certain regulatory developments have also added pressures regarding fee levels. In addition, the recent presidential election in the U.S., and upcoming elections in Europe, have created additional uncertainty as to the future regulatory environment and how it may impact Janus Henderson.

        To the extent that existing or future regulations affecting the sale of Janus Henderson products and services or investment strategies cause or contribute to reduced sales or increased redemptions of its products, impair the investment performance of its products or impact its product mix, Janus Henderson's aggregate assets under management, results of operations or financial condition might be adversely affected.

Janus Henderson may have increased regulatory capital requirements imposed on it by regulators which could negatively impact the combined company's ability to return capital or pay dividends to shareholders or its results of operations and financial condition.

        Janus's and Henderson's regulators typically have broad discretion to impose increased regulatory capital requirements on the regulated entities in their respective groups. It is possible that the regulatory capital requirements that the Janus and Henderson businesses are subject to currently may be subject to change and could increase as a result on the merger (among other factors). The imposition of increased regulatory capital requirements could negatively impact the combined company's ability to return capital or pay dividends to shareholders, restrict its ability to make future acquisitions or, should the company be required to raise additional capital, its results of operations and financial condition.

The U.K. electorate voted in favor of a U.K. exit from the EU in a referendum, which could adversely impact Janus Henderson's business, results of operations and financial condition.

        The U.K. Government held an "in-or-out" referendum in June 2016 on the U.K.'s membership in the EU. The U.K. electorate voted in favor of a U.K. exit from the EU, which we refer to as Brexit. It is expected that a process of negotiation will commence in the first part of 2017 to determine the terms

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of the U.K.'s exit from the EU. At present, it is not possible to predict the outcome of those negotiations or the future relationship the U.K. will have with the EU. However, Janus Henderson will be headquartered and tax resident in the U.K. and conduct business in Europe in part through its U.K. subsidiaries, although it also has European subsidiaries. Depending on the terms of Brexit, Janus Henderson could face new regulatory costs and challenges. For instance, U.K. asset management firms could lose their current level of access to the single EU market and the U.K. may no longer benefit from global trade deals negotiated by the EU on behalf of its members. A decline in trade could affect the attractiveness of the U.K. as a global investment center and, as a result, could have a detrimental impact on U.K. growth. Although Janus Henderson will have an international customer base, it could be adversely affected by reduced growth and greater volatility in the pound sterling and the U.K. economy. There could also be changes to U.K. immigration policy as a result of Brexit, which could lead to operations gravitating towards EU member states. Taken together, these factors could lead to a decline in London's role as a global financial center, particularly if financial institutions move their operations to the EU as a result of the EU financial services passport not having been maintained. Any of the foregoing factors could have a material adverse effect on Janus Henderson's business, results of operations or financial condition.

Harm to Janus Henderson's reputation or poor investment performance of Janus Henderson's products could reduce the level of assets under management or affect sales, potentially negatively impacting the combined company's revenue and net income. Janus Henderson's reputation is critical to the success of the combined company.

        Janus and Henderson believe that their respective brand names have been, and continue to be, well received both in the asset management industry and with their respective clients, reflecting the fact that their brands, like their businesses, are based in part on trust and confidence. If the reputation of Janus or Henderson is harmed, by the process of integrating and rebranding the two businesses following the closing of the merger, existing clients may reduce amounts held in, or withdraw entirely from, funds advised by Janus Henderson or funds may terminate or reduce assets under management under their management agreements with Janus Henderson, which could reduce the amount of assets under management of the combined company and cause the combined company to suffer a corresponding loss in revenue and income. The investment performance of Janus Henderson, along with achieving and maintaining superior distribution and client services, is also critical to the success of the business. Strong investment performance has historically stimulated sales of Janus and Henderson investment products. Poor investment performance as compared to third-party benchmarks or competitive products has in the past (for each separate entity), and could in the future, lead to a decrease in sales of investment products managed by Janus Henderson and stimulate redemptions from existing products, generally lowering the overall level of assets under management and reducing management fees. No assurance can be given that past or present investment performance in the investment products Janus or Henderson manage will be indicative of future performance. Any poor investment performance may negatively impact the revenue and net income of Janus Henderson. The reputation of Janus Henderson could also be damaged by factors such as litigation, regulatory action, loss of key personnel, misconduct, operational failures (including any failures during the integration process), mismanagement, loss of client data, fraud (by employees or third parties), failure to manage conflicts of interest or satisfy fiduciary responsibilities, and negative publicity or press speculation (whether or not any such allegations or claims are valid or ultimately disproved, dismissed or withdrawn). The risk of some or all of these factors occurring and damaging the reputation of Janus Henderson may be increased during integration as Janus Henderson works to combine and rationalize the policies, systems and processes relied upon by each of Janus and Henderson. Reputational harm or poor investment performance may cause Janus Henderson to lose current clients and it may be unable to continue to attract new clients or develop new business. If Janus Henderson fails to address, or appears to fail to address, successfully and promptly the underlying causes of any reputational harm or

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poor investment performance, it may be unsuccessful in repairing any existing harm to its reputation or performance and the combined company's future business prospects would likely be affected.

Failure to establish adequate controls and risk management policies, the circumvention of controls and policies, or fraud could have an adverse effect on the combined company's assets under management, results of operation and financial condition.

        Janus Henderson will have a comprehensive risk management process and will continue to enhance various controls, procedures, policies and systems to monitor and manage risks to its business; however, there can be no assurances that such controls, procedures, policies and systems will successfully identify and manage internal and external risks to the business. Janus Henderson is subject to the risk that its employees, contractors or other third parties may deliberately seek to circumvent established controls to commit fraud or act in ways that are inconsistent with the combined company's controls, policies and procedures (including insider trading). Persistent or repeated attempts involving conflicts of interests, circumvention of policies and controls, fraud or insider trading could have a materially adverse impact on Janus Henderson's reputation and could lead to costly regulatory inquiries.

Failure to properly address conflicts of interest could harm Janus Henderson's reputation, business and results of operations.

        Janus Henderson's business will require continuously managing actual and potential conflicts of interest, including situations where the combined company's services to a particular client conflict, or are perceived to conflict, with the interests of another client or those of Janus Henderson. The risk of actual or potential conflicts of interest occurring may be increased as a result of the merger and it is possible that conflicts between aspects of Janus's and Henderson's existing businesses will be identified during the integration process. The willingness of clients to enter into transactions in which such a conflict might arise may be affected if Janus Henderson fails, or appears to fail, to deal appropriately with conflicts of interest. In addition, potential or perceived conflicts could give rise to litigation or regulatory enforcement actions.

Failure in Janus Henderson's operational or risk management processes, systems or infrastructure could harm Janus Henderson's reputation, business and results of operations.

        Janus Henderson's business is highly dependent on the successful and timely execution of complex investment management, operational, risk management and financial processes. Any operational errors or negligence by the employees of, or others acting on behalf of, Janus Henderson or weaknesses in the internal controls over those processes could result in losses for Janus Henderson, a requirement for Janus Henderson to compensate clients for losses suffered and/or regulatory fines. The risk of such operational errors or of weaknesses in internal controls may be increased during the integration process as the businesses of Janus and Henderson are combined and the processes, systems and controls are rationalized.

        The Janus Henderson business is also highly dependent on the integrity, security and reliability of its information technology systems and infrastructure. If any of the critical systems or infrastructure do not operate properly or are disabled, the ability of Janus Henderson to perform effective investment management on behalf of its clients could be impaired. The risk of such systems and infrastructure failing to operate properly will be increased during the integration process while such systems and infrastructure are combined or replaced. In addition, the failure to maintain an infrastructure commensurate with the size and scope of Janus Henderson's business, including any expansion, could impede the combined company's productivity and growth, which could negatively impact assets under management, results of operations and financial condition.

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Failure to maintain adequate infrastructure could impede Janus Henderson's productivity and ability to support business growth.

        Janus Henderson's infrastructure, including its technological capacity, data centers and office space, will be vital to the operations and competitiveness of its business. The failure to maintain an infrastructure commensurate with the increased size and scope of Janus Henderson's business, including any expansion, could impede the combined company's productivity and growth, which could negatively impact assets under management, results of operations and financial condition and increase operational risk.

Failure to maintain adequate business continuity plans could have a material adverse impact on Janus Henderson and its products.

        Significant portions of Janus Henderson's business operations and those of its critical third-party service providers will be concentrated in a few geographic areas, including the U.K., U.S., Luxembourg and Australia. Should Janus Henderson, or any of its critical service providers, experience a significant local or regional disaster or other business continuity problem, the combined company's continued success will depend in part on the safety and availability of its personnel, its office facilities, and the proper functioning of its computer, telecommunication and other related systems and operations. The failure by Janus Henderson, or any of its critical service providers, to maintain updated adequate business continuity plans, including backup facilities, which will be more difficult during the integration process due to the changing nature of the business during that period, could impede the combined company's ability to operate in the event of a disruption. This could negatively impact the combined company's assets under management, results of operations and financial condition. Janus and Henderson have developed various backup systems and contingency plans but no assurance can be given that they will be adequate in all circumstances that could arise or that material interruptions and disruptions will not occur. In addition, Janus Henderson will rely to varying degrees on outside vendors for disaster contingency support, and, notwithstanding any due diligence or oversight carried out by Janus Henderson, no assurance can be given that these vendors will be able to perform in an adequate and timely manner. If Janus Henderson, or any of its critical service providers, is unable to respond adequately to such an event in a timely manner, the combined company may be unable to continue its business operations, which could lead to a damaged reputation and loss of customers that results in a decrease in assets under management, lower revenue and reduced net income.

Janus Henderson could be subject to losses and reputational harm if the combined company, or its agents, fail to properly safeguard sensitive and confidential information or as a result of cyberattacks.

        Janus Henderson will be dependent on the continued effectiveness of its information and cyber security policies, procedures and capabilities to protect its computer and telecommunications systems and the data that resides in or is transmitted through such systems. The risk of weaknesses in such policies, procedures and capabilities may be increased during the integration process as the businesses of Janus and Henderson are combined and the policies, procedures and systems are rationalized.

        As part of Janus Henderson's normal operations, the combined company will maintain and transmit confidential information about its clients and employees as well as proprietary information relating to its business operations. Janus and Henderson maintain, and Janus Henderson will maintain, a system of internal controls designed to provide reasonable assurance that fraudulent activity, including misappropriation of assets, fraudulent financial reporting and unauthorized access to sensitive or confidential data, is either prevented or detected on a timely basis. Nevertheless, all technology systems remain vulnerable to unauthorized access and may be corrupted by cyberattacks, computer viruses or other malicious software code, the nature of which threats are constantly evolving and becoming increasingly sophisticated. In addition, authorized persons could inadvertently or intentionally release confidential or proprietary information. Although Janus Henderson will take precautions to

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password protect and encrypt its mobile electronic hardware, if such hardware is stolen, misplaced or left unattended, it may become vulnerable to hacking or other unauthorized use, creating a possible security risk and resulting in potentially costly actions by Janus Henderson. Breach or other failure of Janus Henderson's technology systems, including those of third parties with which the combined company does business, or failure to timely and effectively identify and respond to any such breach or failure, could result in the loss of valuable information, liability for stolen assets or information, remediation costs to repair damage caused by the incident, additional security costs to mitigate against future incidents and litigation costs resulting from the incident. Moreover, loss of confidential customer identification information could harm Janus Henderson's reputation, result in the termination of contracts by the combined company's existing customers and subject the combined company to liability under laws that protect confidential personal data, resulting in increased costs or loss of revenue. The increasing prevalence and sophistication of cyberattacks generally and the heightened profile of Janus Henderson as a result of its increased scale and breadth of global activities may result in an increase in the volume and sophistication of cyberattacks on Janus Henderson specifically. This may increase the amount of investment that the combined company will need to make to minimize the risk of harm to its business and potentially increase the risk that, despite such investment, the combined company will be a victim of a successful cyberattack. Recent well-publicized security breaches at other companies have exposed failings by companies to keep pace with the threats posed by cyberattackers and have led to enhanced government and regulatory scrutiny of the measures taken by companies to protect against cyberattacks, and may in the future result in heightened cyber security requirements, including additional regulatory expectations for oversight of vendors and service providers which could lead to increased costs or fines or public censure which could lead to a damaged reputation and loss of customers (and a decrease in assets under management, lower revenue and reduced net income) as a result.

Failure to comply with client contractual requirements and/or investment guidelines could negatively impact the combined company's assets under management, results of operations and financial condition.

        Many of the investment management agreements under which the combined company will manage assets or provide services will specify investment guidelines or requirements that Janus Henderson will be required to observe in the provision of its services. Laws and regulations will also impose similar requirements for certain accounts. A failure to follow these guidelines or requirements could result in damage to Janus Henderson's reputation or in clients seeking to recover losses, withdrawing their assets or terminating their contracts, any one of which could cause revenues and profitability to decline. In addition breach of these investment guidelines or requirements could result in regulatory investigation, censure and/or fine. The risk of breach of such investment guidelines or requirements may be increased during the integration process as the businesses of Janus and Henderson are combined.

Janus Henderson may be subject to claims of lack of suitability.

        If clients of Janus Henderson suffer losses on funds or investment mandates managed by the combined company, they may seek compensation from Janus Henderson on the basis of allegations that the funds and/or investment mandates were not suitable for such clients or that the fund prospectuses or other marketing materials contained material errors or were misleading. Despite the controls relating to disclosure in fund prospectuses and marketing materials, it is possible that such action may be successful, which in turn could adversely affect the business, financial condition and results of operations of the combined company. Any claim for lack of suitability may also result in regulatory investigation, censure and/or fine and may damage the reputation of Janus Henderson.

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Janus Henderson's business may be vulnerable to failures of support systems and client service functions provided by third-party vendors.

        Janus Henderson's client service capabilities as well as its ability to obtain prompt and accurate securities pricing information and to process client transactions and reports will be significantly dependent on communication and information systems and services provided by third-party vendors. The ability to consistently and reliably obtain securities pricing information, process client transactions and provide reports and other client services to the shareholders of funds and other investment products managed by Janus Henderson will be essential to the combined company's operations. Any delays, errors or inaccuracies in obtaining pricing information, processing client transactions or providing reports, and any other inadequacies in other client service functions could impact client relationships, result in financial loss and potentially give rise to regulatory action and claims against Janus Henderson. A failure of third-party systems or services could adversely affect Janus Henderson's assets under management, results of operations and financial condition.

The failure of one of Janus Henderson's third-party service providers or other key vendors to fulfill its obligations could have a material adverse effect on the combined company's reputation or business, which could negatively impact the combined company's assets under management, results of operations and financial condition.

        Janus Henderson will depend on third-party service providers and other key vendors for various fund administration, accounting, custody, risk analytics, market data, market indices and transfer agent roles, and other distribution and operational needs. If Janus Henderson's third-party service providers or other key vendors fail to fulfill their obligations, experience service interruptions or otherwise provide inadequate service, it could lead to operational and regulatory problems, including with respect to certain of the combined company's products, which could result in losses, enforcement actions, or reputational harm and which could negatively impact the combined company's, assets under management, results of operations and financial condition.

Janus's and Henderson's businesses are dependent on investment management agreements that are subject to termination, non-renewal or reductions in fees.

        Janus and Henderson derive revenue from investment management agreements with investment funds, institutional and other investors. With respect to investment management agreements with U.S. mutual funds, these agreements may be terminated by either party with notice, or in the event of an "assignment" (as defined in the Investment Company Act), and must be approved and renewed annually by the independent members of each fund's board of directors or trustees or its shareowners, as required by law. In addition, the board of directors or trustees of certain investment funds and institutional and other investors generally may terminate their investment management agreements upon written notice for any reason and without penalty. Such U.S. mutual funds, investments funds or other investors may choose to exercise such termination rights as a result of the uncertainty caused by the merger or if the employees with whom they have a relationship leave the business during or following the integration process. The termination of or failure to renew one or more of these agreements or the reduction of the fee rates applicable to such agreements could have a material adverse effect on the combined company's assets under management, results of operations and financial condition.

Janus Henderson could be impacted by counterparty or client defaults.

        In periods of significant market volatility, the deteriorating financial condition of one financial institution may materially and adversely impact the performance of others. Janus and Henderson, and the funds and accounts they manage, have exposure to many different counterparties, and routinely execute transactions with counterparties across the financial industry. Following the closing of the

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merger, Janus Henderson will have a greater exposure to such counterparties than Janus or Henderson on a standalone basis and, following the integration process, the concentration of its exposure to certain of those counterparties may increase. Janus Henderson, and the funds and accounts it manages, may be exposed to credit, operational or other risk in the event of a default by a counterparty or client, or in the event of other unrelated systemic market failures.

Janus Henderson's indebtedness could adversely affect its financial condition and results of operations.

        Janus Henderson's indebtedness could limit its ability to obtain additional financing for working capital, capital expenditures, acquisitions, debt servicing requirements or other purposes. Debt servicing requirements will increase Janus Henderson's vulnerability to adverse economic, market and industry conditions; limit Janus Henderson's flexibility in planning for or reacting to changes in business operations or to the asset management industry overall; and place Janus Henderson at a disadvantage in relation to competitors that have lower debt levels. Any or all of the above events and factors could adversely affect Janus Henderson's assets under management, results of operations and financial condition.

Janus Henderson could be adversely impacted by changes in assumptions used in calculating pension assets and liabilities.

        Henderson provides retirement benefits for its current and former employees in the U.K. through the Henderson Group Pension Scheme, which we refer to as the U.K. Pension Scheme. The U.K. Pension Scheme operates a number of defined benefit sections, which closed to new entrants on November 15, 1999, and a money purchase section. As at December 31, 2014, the U.K. Pension Scheme had a funding deficit of £29 million on a technical provisions basis. On the IAS19 accounting basis the U.K. Pension Scheme showed a surplus of £145.9 million as at December 31, 2016.

        Henderson may be required to increase its contributions in the future to cover any increased funding shortfall and/or expenses in the U.K. Pension Scheme, which could adversely impact Janus Henderson's results and financial condition.

        The following issues could adversely affect the funding of the defined benefits under the U.K. Pension Scheme and materially affect Janus Henderson's funding obligations: (i) poorer than anticipated investment performance of pension fund investments; (ii) the trustees of the U.K. Pension Scheme switching investment strategy to one with a lower weighting of return-seeking assets; (iii) changes in the corporate bond yields which are used in the measurement of the U.K. Pension Scheme's liabilities; (iv) longer life expectancy (which will make pensions payable for longer and therefore more expensive to provide, whether paid directly from the U.K. Pension Scheme or secured by the purchase of annuities); (v) adverse annuity rates (which tend, in particular, to depend on prevailing interest rates and life expectancy), as these will make it more expensive to secure pensions with an insurance company; (vi) a change in the actuarial assumptions by reference to which Henderson's contributions are assessed, for example changes to assumptions for long term price inflation; (vii) any increase in the risk-based levy assessed by and payable to the Pension Protection Fund by the U.K. Pension Scheme; (viii) other events occurring which make past service benefits more expensive than predicted in the actuarial assumptions by reference to which Henderson's past contributions were assessed; (iv) changes to the regulatory regime for funding defined benefit pension schemes in the U.K.; and (x) the U.K. Pensions Regulator exercising its power to trigger a winding up of the U.K. Pension Scheme thereby triggering a buy-out debt on the employers or the U.K. Pensions Regulator using its powers under the Pensions Act 2004 to make other members of the Janus Henderson group liable for any deficit in the U.K. Pension Scheme's funding (although, in practice, it is assumed that the Pensions Regulator would be unlikely to exercise these powers while Henderson continues to fund the U.K. Pension Scheme appropriately).

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Janus and Henderson are periodically involved in various legal proceedings and regulatory matters and Janus Henderson may be involved in such proceedings in the future.

        Janus and Henderson and their respective employees are periodically involved in various legal proceedings and regulatory investigations. Among other things, such matters may result in fines, censure, suspension of personnel and revocation of licenses. Any of these outcomes could adversely affect Janus Henderson's assets under management, results of operations and financial condition. Additionally, Janus and Henderson and their respective employees have received and may receive in the future requests for information in connection with certain investigations or proceedings from various governmental and regulatory authorities. Following the closing of the merger, Janus Henderson will be subject to any legal proceedings and regulatory investigations that either Janus or Henderson were involved in prior to closing, and may be subject to new proceedings or investigations relating to facts or circumstances that occurred in respect of Janus or Henderson prior to the closing of the merger. These investigations or proceedings may result in increased costs or reputational harm to the combined company, which may lower sales and increase redemptions.

Insurance may not be available on a cost-effective basis to help protect Janus Henderson from potential liabilities.

        Janus Henderson faces the inherent risk of liability related to litigation from clients, third-party vendors or others. To help protect against these potential liabilities, Janus and Henderson have, and Janus Henderson will in the future, purchase insurance in amounts, and against risks, that Janus Henderson considers appropriate, where such insurance is available at prices it deems acceptable. There can be no assurance, however, that a claim or claims will be covered by insurance or, if covered, will not exceed the limits of available insurance coverage, that any insurer will remain solvent and will meet its obligations to provide Janus Henderson with coverage or that insurance coverage will continue to be available with sufficient limits at a reasonable cost. Insurance costs are impacted by market conditions and the risk profile of the insured, and may increase significantly over relatively short periods. In addition, certain insurance coverage may not be available or may only be available at prohibitive costs. Renewals of insurance policies may expose Janus Henderson to additional costs through higher premiums or the assumption of higher deductibles or co-insurance liability.

Janus Henderson will have significant goodwill and intangible assets that are subject to impairment.

        At December 31, 2016, Henderson's goodwill and intangible assets totaled $1.1 billion and the additional goodwill and intangible assets arising on the merger is provisionally estimated to be approximately $3.2 billion. The value of these assets may not be realized for a variety of reasons, including, but not limited to, significant redemptions, loss of clients, damage to brand name and unfavorable economic conditions. Janus and Henderson have recorded goodwill and intangible asset impairments in the past and Janus Henderson could incur similar charges in the future. Under U.S. GAAP, goodwill and intangible assets with indefinite lives are not amortized but are tested for impairment annually, or more often if an event or circumstance indicates that an impairment loss may have been incurred. Other intangible assets with a finite life are amortized on a straight-line basis over their estimated useful lives and reviewed for impairment whenever there is an indication of impairment. Should such reviews indicate impairment, a reduction of the carrying value of the intangible asset could occur, resulting in a charge that may, in turn, adversely affect Janus Henderson's assets under management, results of operations and financial condition.

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Risks Related to Taxes

Additional tax liabilities could have a material impact on Janus Henderson's financial condition, results of operations and/or liquidity.

        The members of the Janus Henderson group operate in a number of territories, and will accordingly be subject to tax in several jurisdictions. The tax rules to which the members of the Janus Henderson group are subject are complex, and each member, and the group as a whole, must make judgments (including certain judgments based on external advice) as to the interpretation and application of these rules.

        The tax affairs of members of the Janus Henderson group will in the ordinary course be reviewed by tax authorities, which may disagree with certain positions that Janus and/or Henderson have taken, or that members of the Janus Henderson group have taken or will take in the future, and assess additional taxes. Janus and Henderson regularly assess the likely outcomes of such tax inquiries, investigations or audits in order to determine the appropriateness of their respective tax provisions. However, there can be no assurance that Janus or Henderson will accurately predict the outcomes of these inquiries, investigations or audits, and the actual outcomes of these inquiries, investigations or audits could have a material impact on Janus Henderson's financial results.

        Janus and Henderson are subject to ongoing routine tax inquiries, investigations or audits in various jurisdictions.

The IRS may not agree with the conclusion that Janus Henderson is to be treated as a foreign corporation for U.S. federal income tax purposes following the merger or may assert that Janus Henderson is subject to certain adverse consequences for U.S. federal income tax purposes following the merger.

        Although Henderson is incorporated and registered in Jersey, Channel Islands, and is treated as (and Janus Henderson after the merger is expected to be treated as) tax resident in the U.K., the IRS may assert that Janus Henderson, as a result of the merger, should be treated as a U.S. corporation (and, therefore, a U.S. tax resident) for U.S. federal income tax purposes pursuant to section 7874 of the Code (referred to as "section 7874"). Under current U.S. federal income tax law, a corporation will generally be considered to be resident for U.S. federal income tax purposes in its place of organization or incorporation. Accordingly, under the generally applicable U.S. federal income tax rules, Janus Henderson would generally be classified as a non-U.S. corporation (and, therefore, not a U.S. tax resident).

        Section 7874 and the Treasury regulations promulgated thereunder, however, contain specific rules that may cause a non-U.S. corporation to be treated as a U.S. corporation for U.S. federal income tax purposes under certain circumstances.

        Section 7874 provides that if, following an acquisition of a U.S. corporation by a non-U.S. corporation, at least 80% of the acquiring non-U.S. corporation's stock (by vote or value) is considered to be held by former shareholders of the U.S. corporation by reason of holding stock of such U.S. corporation (such percentage referred to as the "ownership percentage" and such test referred to as the "ownership test"), and the "expanded affiliated group" which includes the acquiring non-U.S. corporation does not have substantial business activities in the country in which the acquiring non-U.S. corporation is created or organized, then the non-U.S. corporation would be treated as a U.S. corporation for U.S. federal income tax purposes even though it is a corporation created and organized outside the U.S. This test is referred to herein as the "80% test."

        Based on currently available data, the parties do not expect section 7874—either the 60% test (as described below) or the 80% test—to apply to the merger. Whether the ownership test has been satisfied, however, is determined only after the closing of the merger. For example, for purposes of determining the ownership percentage of the former Janus stockholders, the former Janus stockholders

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will be deemed to own an amount of Janus Henderson ordinary shares in respect of certain prior distributions (including stock repurchases) by Janus prior to the closing of the merger. Further, there is limited guidance regarding the application of section 7874, and changes in law between the date of this proxy/prospectus and the closing of the merger could also alter this analysis.

        If Janus Henderson were treated as a U.S. corporation for U.S. federal income tax purposes, it could be liable for substantial additional U.S. federal income tax on its operations and income following the closing of the merger. Additionally, if Janus Henderson were treated as a U.S. corporation for U.S. federal income tax purposes, non-U.S. Janus Henderson shareholders would generally be subject to U.S. withholding tax on the gross amount of any dividends paid by Janus Henderson to such shareholders.

        In addition, if the ownership percentage is equal to or greater than 60% but less than 80%, then the U.S. corporation and its affiliates could be prohibited from using their foreign tax credits or other attributes to offset the income or gain recognized by reason of the transfer of property to a non-U.S. related person or any income received or accrued by reason of a license of any property by such U.S. entity to a non-U.S. related person. Further, certain Janus stock compensation held directly or indirectly by management would be subject to an excise tax at a rate equal to 15%. In addition, under U.S. Treasury temporary regulations, Janus Henderson's ability to integrate certain non-U.S. operations or to access cash earned by non-U.S. subsidiaries may be limited. This test is referred to herein as the "60% test."

        Janus has requested that Skadden render an opinion, which will be dated on or after the closing date of the merger and which will be based on certain facts, representations, covenants, and assumptions, that the merger should not be subject to section 7874. Whether such opinion can be given will depend on the facts as of the closing date. Moreover, if such opinion is rendered, there can be no assurance that the IRS will agree with the position that Janus Henderson is to be treated as a non-U.S. corporation or that Janus Henderson is not to be subject to the other adverse tax consequences associated with having an ownership fraction that is equal to or greater than 60% but less than 80%. In addition, the receipt of an opinion from Skadden with respect to section 7874 is not a condition to the closing of the merger, nor have the parties applied for a ruling from the IRS.

        Please see the section entitled "The Merger—U.S., U.K. and Jersey Tax Considerations—U.S. Federal Income Tax Considerations for U.S. Holders" beginning on page 131 for a full discussion of the application of section 7874 to the merger.

Future changes to tax laws could adversely affect Janus Henderson.

        Any change in tax law, interpretation or practice, or in the terms of tax treaties, in a jurisdiction where Janus Henderson is subject to tax could increase the amount of tax payable by the combined company and/or the Janus Henderson group.

        As discussed above, under current law, Janus Henderson is expected to be treated as a non-U.S. corporation for U.S. federal income tax purposes. In addition to the potential application of section 7874, however, recent legislative proposals have also aimed to expand the scope of U.S. corporate tax residence, including in such a way as would cause Janus Henderson to be treated as a U.S. corporation if the management and control of the combined company and its affiliates were determined to be located primarily in the U.S.

        In addition, the U.S. Congress, the Organization for Economic Co-operation and Development, which we refer to as the OECD, and other government agencies in jurisdictions where Janus and Henderson and their respective affiliates do business have had an extended focus on issues related to the taxation of multinational corporations. One example is the OECD's "base erosion and profit shifting" project, which focuses on limiting the ability of companies to shift income, losses, and

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deductions based on relative tax rates. A number of tax authorities have indicated that they will consider reforms to their tax laws in response to this project and on June 20, 2016 the EU Council adopted the Anti Tax Avoidance Directive (EU) 2016/1164, which requires member states to implement certain of the OECD's recommendations. As a result of the OECD project and the focus on the taxation of multi-national corporations, the tax laws in the U.S., the U.K., and other countries in which Janus and Henderson and their respective affiliates do business could change on a prospective or retroactive basis, and any such changes could adversely affect Janus Henderson after the merger.

        Furthermore, the U.S. Congress and the current Administration under President Trump have indicated a desire to reform the U.S. corporate income tax. There is a substantial lack of clarity around the likelihood, timing and details of any such tax reform. At this time, it is not possible to determine whether such reform could adversely affect Janus Henderson's assets under management, results of operation, or financial condition.

The merger may fail to qualify as a reorganization within the meaning of section 368(a) of the Code or may be subject to section 367(a)(1) of the Code, potentially causing U.S. holders of Janus common stock to recognize taxable gain.

        Assuming, as the parties intend, that the merger is treated as a reorganization under section 368(a) of the Code and that the merger is not subject to section 367(a)(1) of the Code, if you are a U.S. holder of Janus common stock and you exchange all of your Janus common stock for Henderson ordinary shares in the merger, you should not recognize any gain or loss with respect to your Janus stock, except to the extent of any cash you may receive in lieu of a fractional share.

        Although the parties intend that the merger will qualify as a tax free reorganization within the meaning of section 368(a) of the Code and that the merger will not be subject to section 367(a)(1) of the Code, until the closing, the parties cannot definitively determine the tax treatment of the merger. In addition, no assurance can be given that the IRS will not assert, or that a court would not sustain, that the merger does not qualify as a reorganization within the meaning of section 368(a) of the Code or that the merger is subject to section 367(a)(1) of the Code.

        If section 367(a)(1) of the Code were to apply to the merger, a U.S. holder of Janus common stock would recognize gain (but not loss) in an amount equal to the excess, if any, of the fair market value, as of the closing date of the merger, of Henderson ordinary shares received in the merger plus cash received in lieu of fractional shares, over such U.S. holder's basis in the shares of Janus common stock surrendered by the U.S. holder in the merger. Any gain so recognized would generally be long-term capital gain if the U.S. holder had held the Janus common stock for more than one year at the time the merger is completed.

        Janus has requested that Skadden render its opinion to Janus, which will be dated on or after the closing date of the merger and be based on certain facts, representations, covenants, and assumptions, that the merger should be treated as a tax-free reorganization under section 368(a) of the Code and that section 367(a)(1) of the Code should not apply to the merger. Whether such opinion can be given will depend on the facts as of the closing date. Moreover, if such opinion is rendered, there can be no assurance that the IRS will agree with the conclusions expressed therein. The obligation of Janus and Henderson to consummate the merger, however, is not conditioned upon the receipt of such opinion from Skadden or any other counsel, nor have the parties applied for a ruling from the IRS.

        For a more complete description of the U.S. federal income tax consequences of the merger, please see the section entitled "The Merger—U.S., U.K. and Jersey Tax Considerations—U.S. Federal Income Tax Considerations for U.S. Holders" beginning on page 131.

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If Henderson is, or if Janus Henderson were to become, a passive foreign investment company (a "PFIC") for U.S. federal income tax purposes, U.S. holders of Janus Henderson ordinary shares would be subject to certain adverse U.S. federal income tax consequences.

        In general, a non-U.S. corporation will be a PFIC for any taxable year if (i) 75% or more of its gross income consists of passive income or (ii) 50% or more of the average quarterly value of its assets consists of assets that produce, or are held for the production of, passive income. Henderson believes that it was not a PFIC for its taxable year prior to the merger, and Janus and Henderson do not expect Janus Henderson to be a PFIC for its first taxable year that includes the merger or in the foreseeable future. There can be no assurance, however, that Janus Henderson will not be considered a PFIC for any taxable year. If Janus Henderson were a PFIC for any taxable year during which a U.S. investor held Janus Henderson ordinary shares, such investor would generally be subject to certain adverse U.S. federal income tax consequences, such as ineligibility for any preferred tax rates on capital gains or on actual or deemed dividends, the application of additional taxes equal to interest charges generally applicable to underpayments of tax on certain distributions and sales, and additional reporting requirements under U.S. federal income tax laws and regulations.

        For a more complete description of the rules relating to PFICs, please see the section entitled "The Merger—U.S., U.K. and Jersey Tax Considerations—U.S. Federal Income Tax Considerations for U.S. Holders" beginning on page 131.

Henderson is, and Janus Henderson intends to be, tax resident in the U.K. and nowhere else. However, were Janus Henderson to be treated as tax resident in an alternative and/or additional jurisdiction, this could increase the aggregate tax burden on Janus Henderson and its shareholders.

        Janus Henderson is and will remain incorporated and registered in Jersey, Channel Islands, so will not be presumed automatically to be U.K. resident for tax purposes. The senior management of Janus Henderson intends to meet all requirements to establish U.K. tax residency by establishing that central management and control of the combined company rests in the U.K. If U.K. tax residency is not established or maintained, this could increase the amount of tax payable or suffered by the Janus Henderson group.

Risks Related to the Business Combination

The combined company may fail to realize the anticipated benefits of the merger.

        The success of the merger will depend on, among other things, the combined company's ability to combine the Janus and Henderson businesses in a manner that realizes anticipated synergies and meets or exceeds the projected stand-alone cost savings and revenue growth trends anticipated by each company. On a combined basis, Janus Henderson expects to benefit from recurring annual run-rate pre-tax net cost synergies, expected to be fully executed within three years following closing, that will exceed the cost reductions that could be achievable by Janus and Henderson through stand-alone cost reduction programs. Such cost synergies are expected to be realized by reducing combined headcount in internal support functions, investment management and trading functions and distribution and marketing functions and consolidation of offices in overlapping locations and other actions.

        If the combined company is not able to successfully achieve these objectives, or the cost to achieve these synergies is greater than expected, then the anticipated benefits of the merger may not be realized fully or at all or may take longer to realize than expected.

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The unaudited pro forma condensed combined financial statements included in this proxy statement/prospectus may not reflect the actual financial condition and results of operations of Janus Henderson after the merger.

        This proxy statement/prospectus includes unaudited pro forma condensed combined financial statements for the combined company, which give effect to the merger, and should be read in conjunction with the financial statements and accompanying notes of Janus and Henderson which are included or incorporated by reference in this proxy statement/prospectus. The pro forma financial statements are presented for informational purposes only and are not necessarily indicative of what the combined company's actual financial condition or results of operations would have been had the merger been completed on the dates indicated. Accordingly, the combined company's business, assets under management, results of operations and financial condition may differ significantly from those indicated by the pro forma financial statements included in this proxy statement/prospectus. For more information, see "Unaudited Pro Forma Condensed Combined Financial Information."

Combining the businesses of Janus and Henderson may be more difficult, costly or time-consuming than expected, which may adversely affect the combined company's results and negatively affect the value of Janus Henderson ordinary shares following the merger.

        Janus and Henderson have entered into the merger agreement because each believes that the merger will be beneficial to its respective company and stockholders or shareholders, as applicable, and that combining the businesses of Janus and Henderson will produce cost synergies and other benefits. However, Janus and Henderson have historically operated as independent companies and will continue to do so until the closing of the merger. Following the closing of the merger, the combined company's management will need to integrate Janus's and Henderson's respective businesses. The combination of two independent businesses of the size and scale of Janus and Henderson is a complex, costly and time consuming process and the management of the combined company may face significant challenges in implementing such integration, some of which may be beyond their control including, without limitation:

        Some of these factors will be outside of the control of Henderson and Janus and any one of them could result in increased costs or decreased revenue which could materially impact the combined company's business, financial conditions and results of operations as well as increase the risk of operational errors due to management teams being diverted from ongoing business concerns which

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could have negative reputational or regulatory impacts. The integration process and other disruptions resulting from the merger may also adversely affect the combined company's relationships with employees, customers, and others with whom Janus and Henderson have business or other dealings, and difficulties in integrating the businesses or regulatory functions of Janus and Henderson could harm the reputation of the combined company.

        If the combined company is not able to combine the businesses of Janus and Henderson successfully in an efficient, cost-effective and timely manner, the anticipated benefits and cost synergies of the merger may not be realized fully, or at all, or may take longer to realize than expected, and the value of Janus Henderson ordinary shares, the revenue, levels of expenses and results of operations of the combined company may be affected adversely. If the combined company is not able to adequately address integration challenges, the combined company may be unable to successfully realize the anticipated benefits of the merger.

Janus and Henderson have incurred, and the combined company expects to incur, additional significant costs in connection with the integration of the combined company.

        There are a large number of processes, policies, procedures, operations, technologies and systems that must be integrated in connection with the merger. While both Janus and Henderson have assumed that a certain level of expenses would be incurred in connection with the merger and the other transactions contemplated by the merger agreement, there are many factors beyond their control that could affect the total amount of, or the timing of, anticipated expenses with respect to the integration and implementation of the combined businesses.

        There may also be additional unanticipated significant costs in connection with the merger that the combined company may not recoup. These costs and expenses could reduce the benefits and additional income Janus and Henderson expect to achieve from the merger. Although Janus and Henderson expect that the benefits of the merger will offset the transaction expenses and integration costs over time, no assurance can be given that any benefits will be achieved in the near term, if at all.

Inability to access the debt capital markets could impair Janus Henderson's liquidity, business or financial condition.

        Each of Janus and Henderson has utilized in the past and Janus continues to utilize the debt capital markets as a source of finance. An inability to raise money in the debt markets could limit the combined company's ability to secure additional financing (if required). The combined company's access to the debt markets in amounts adequate to finance its activities could be impaired as a result of various factors, some of which are not specific to the combined company, such as a severe disruption of the financial markets and interest rate fluctuations.

        The costs and availability of financing from the debt capital markets will also be dependent on the creditworthiness of members of the combined company. The level and quality of the combined company's earnings, operations, business and management, among other things, will impact its creditworthiness and potentially any credit ratings assigned by rating agencies to members of the combined company. A decrease in credit ratings assigned to members of the combined company by the ratings agencies may, to the extent that the combined company wishes to secure further borrowing, negatively impact the combined company's access to the debt capital markets and increase the combined company's cost of borrowing. It may also impact investor confidence in the combined company and consequently reduce the level of assets under management or affect sales. There can be no assurance that the combined company will have a credit rating assigned to it by rating agencies or maintain the current credit rating of Janus on a stand-alone basis. Any actual or anticipated changes or downgrades in such credit ratings may have a negative impact on the combined company.

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Following the closing of the transaction, the combined company may launch branding or rebranding initiatives that may involve substantial costs and may not be favorably received by customers.

        Following closing of the transaction, the combined company corporate name will be Janus Henderson Group plc. Following this, the combined company may incur substantial costs in rebranding its products and services, and the combined company may not be able to achieve or maintain brand name recognition or status under the new combined company brand that is comparable to the recognition and status previously enjoyed by Janus and Henderson separately. The failure of any such rebranding initiative could adversely affect the combined company's ability to attract and retain customers after the closing of the transaction, which could cause the combined company not to realize some or all of the benefits contemplated by Janus and Henderson to result from the closing of the transaction.

An impairment of goodwill or other intangible assets would adversely affect Janus Henderson's financial condition and results of operations.

        Upon closing of the merger, a significant portion of the difference between the purchase price, Janus's net assets at that date and the allocation of costs of the combination to the assets acquired and the liabilities assumed will be recorded as goodwill. In addition, other intangible assets will be recorded as a result of the purchase price allocation. Under U.S. GAAP, which will be the accounting principles of Janus Henderson following the closing of the merger, goodwill and intangible assets with indefinite lives are not amortized but are tested for impairment annually, or more often if an event or circumstance indicates that an impairment loss may have been incurred. Other intangible assets with a finite life are amortized on a straight-line basis over their estimated useful lives and reviewed for impairment whenever there is an indication of impairment. In particular, if the combination of the businesses meets with unexpected difficulties, or if the combined company's business does not develop as expected, impairment charges may be incurred in the future which could be significant and which could have an adverse effect on the combined company's financial condition and results of operations.

Following the merger, Janus Henderson will be a foreign private issuer under the rules and regulations of the SEC and will therefore qualify for certain accommodations under the U.S. securities laws, which may result in less information being made available about Janus Henderson than is currently made available about Janus and/or Janus stockholders being provided with less protection than at present.

        Following the merger, Janus Henderson will retain its status as a foreign private issuer, or FPI, until at least the end of the 2017 fiscal year. For so long as Janus Henderson retains its FPI status, Janus Henderson will qualify for certain accommodations under the U.S. securities laws, including (i) being subject to reduced disclosure requirements with respect to quarterly reporting and executive compensation, (ii) not being subject to the proxy rules under the Exchange Act, Section 16 of the Exchange Act or Regulation FD, and (iii) being able to follow certain home country rules in lieu of domestic company requirements under NYSE rules. While Janus Henderson will report its financial results in accordance with U.S. GAAP and intends to file its annual and interim reports on Forms 10-K and 10-Q, regardless of whether Janus Henderson continues to qualify as an FPI following closing of the merger, Janus Henderson will not be required to file such domestic U.S. company reports and may not file periodic reports and financial statements with the SEC as frequently or as promptly as domestic U.S. companies with securities registered under the Exchange Act for so long as Janus Henderson retains its status as an FPI. During this time period, Janus Henderson will also not be required to comply with the proxy rules, which impose certain disclosure and procedural requirements for proxy solicitations under Section 14 of the Exchange Act, Regulation FD, which imposes certain restrictions on the selective disclosure of material information, and Janus Henderson's officers, directors and principal shareholders will be exempt from the reporting and "short-swing" profit recovery provisions of Section 16 of the Exchange Act and the rules under the Exchange Act with respect to their purchases

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and sales of Janus Henderson ordinary shares. Accordingly, after the merger, if you continue to hold Janus Henderson ordinary shares, you may receive less information about Janus Henderson than you currently receive about Janus.

        As a foreign private issuer, Janus Henderson may also follow certain corporate governance practices permitted under its home country rules instead of those otherwise required under the applicable rules of the NYSE for domestic U.S. issuers for so long as Janus Henderson retains foreign private issuer status. Janus and Henderson currently intend for Janus Henderson to generally follow the NYSE corporate governance requirements applicable to a domestic company upon closing of the merger, although Janus Henderson will not be obligated to do so. Were Janus Henderson to follow corporate governance practices permitted under home country rules as opposed to the requirements that would otherwise apply to a domestic U.S. company listed on the NYSE, you may not receive the same corporate governance protections as a Janus Henderson shareholder as you currently have as a Janus stockholder.

Risks Related to the Merger

Janus stockholders cannot be sure of the value of the merger consideration they will receive.

        Janus stockholders will receive a fixed number of Henderson ordinary shares (per share of Janus common stock) in the merger, rather than a number of Henderson ordinary shares with a particular fixed market value. The market value of Henderson ordinary shares at the effective time may vary significantly from their prices on the date prior to the date the merger agreement was executed, the date of this proxy statement/prospectus or the date on which Janus stockholders vote on the Janus merger proposal. All of the merger consideration to be received by Janus stockholders will be Henderson ordinary shares (other than cash in lieu of fractional shares, based on then prevailing market prices, received by Janus stockholders). At the time of the Janus special meeting, Janus stockholders will not know or be able to determine the value of the Henderson ordinary shares they will receive upon closing of the merger. Changes in the market prices of Henderson ordinary shares may result from a variety of factors that are beyond the control of Henderson, including changes in its business, operations and prospects, regulatory considerations, governmental actions, and legal proceedings and other developments. Market assessments of the benefits of the merger, the likelihood that the merger will be completed and general and industry-specific market and economic conditions may also have an effect on the market price of Henderson ordinary shares. Changes in market prices of Henderson ordinary shares may also be caused by fluctuations and developments affecting industry-specific and general economic and market conditions and may have an adverse effect on Henderson ordinary shares prior to consummation of the merger.

        You are urged to obtain up-to-date prices for Henderson ordinary shares. Further, neither Janus nor Henderson is permitted to terminate the merger agreement solely because of changes in the market prices of Henderson ordinary shares. See "Comparative Per Share Market Price and Dividend Information" for ranges of historic prices of Janus common stock and Henderson ordinary shares.

The market price for the combined company's ordinary shares may be affected by factors different from those that historically have affected Janus common stock and Henderson ordinary shares.

        Upon closing of the merger, holders of shares of Janus common stock (other than any shares held in treasury) will become holders of Janus Henderson ordinary shares. Janus and Henderson each have businesses that differ from each other. Accordingly, the results of operations of the combined company will be affected by some factors that are different from those currently affecting the results of operations of each of Henderson and Janus. For a discussion of the businesses of Janus and Henderson and of certain important factors to consider in connection with those businesses, see the sections of this proxy statement/prospectus entitled "Business of Henderson," "—Risks Related to the Combined Business of Janus and Henderson" and the documents incorporated by reference in this proxy statement/prospectus and referred to under "Where You Can Find More Information" in this proxy statement/prospectus.

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Janus or Henderson may waive one or more of the closing conditions without re-soliciting shareholder approval.

        Janus or Henderson may determine to waive, in whole or in part, one or more of the conditions to its obligations to consummate the merger. Janus and Henderson currently expect to evaluate the materiality of any waiver and its effect on Janus stockholders or Henderson shareholders, as applicable, in light of the facts and circumstances at the time to determine whether any amendment of this proxy statement/prospectus or any re-solicitation of proxies or voting cards is required in light of such waiver. Any determination whether to waive any condition to the merger or as to re-soliciting stockholder approval or amending this proxy statement/prospectus as a result of a waiver will be made by Janus or Henderson, as applicable, at the time of such waiver based on the facts and circumstances as they exist at that time.

The merger agreement may be terminated in accordance with its terms and the merger may not be completed.

        The closing of the merger is subject to the satisfaction or waiver of a number of conditions. Those conditions include: (i) approval of the Janus merger proposal, (ii) approval of (a) the merger and the other transactions contemplated by the merger agreement and the Dai-ichi agreements, the allotment of the Henderson ordinary shares in connection therewith and the Henderson share issuance proposal by the affirmative vote of a majority of the Henderson shareholders, (b) the Henderson amended articles proposal, (c) the Henderson name change proposal, (d) the Henderson permitted dividend proposal and (e) the Henderson LSE de-listing proposal, (iii) certain regulatory approvals, including (a) expiration or termination of the waiting periods under the HSR Act, (b) approval from FINRA pursuant to NASD Rule 1017, (c) the required approvals from the FCA for Henderson to acquire control of each subsidiary of Janus that is authorized by the FCA and (d) the approval by the JFSC of this proxy statement/prospectus, the registration statement of which this proxy statement/prospectus forms a part and any other relevant document deemed to be a prospectus pursuant to the Jersey Companies Law, and the issue by the JFSC of any consent required pursuant to the Control of Borrowing (Jersey) Order 1958 for Henderson to lawfully assume the Janus awards and plans, (e) consents, non-objections and/or approvals from the applicable governmental authorities in Canada, Hong Kong, Ireland, Singapore, Switzerland and, if applicable, Australia, India and Jersey and certain other non-U.S. jurisdictions and (f) consents, non-objections and/or approvals from the applicable governmental authorities in Jersey, Switzerland and, if applicable, Ireland necessary in connection with the transactions contemplated by the Dai-ichi agreements, (iv) the SEC having declared effective the registration statement of which this proxy statement/prospectus forms a part, and the Janus Henderson ordinary shares having been approved for listing on the NYSE, (v) the absence of judgments, orders or decrees preventing or making illegal the consummation of the merger, (vi) approval by the boards of trustees and shareholders of Janus-advised U.S. mutual funds of new investment advisory agreements with Janus to take effect at the closing of the merger representing at least 67.5% of the assets under management of those funds as of September 30, 2016, and (vii) the absence of breach of the representations and warranties by Henderson and Janus (subject to materiality and "material adverse effect" qualifications in certain cases) and material compliance by each of Henderson and Janus with its covenants. These conditions to the closing may not be fulfilled and, accordingly, the merger may not be completed.

        If the merger is not completed by September 30, 2017, either Janus or Henderson may choose not to proceed with the merger. In addition, the parties can mutually decide to terminate the merger agreement at any time prior to consummation of the merger, before or after the required Janus and Henderson shareholder approvals. In addition, Janus or Henderson may elect to terminate the merger agreement in certain other circumstances.

        If the merger agreement is terminated, Henderson and Janus may incur substantial fees in connection with termination of the merger agreement and will not recognize the anticipated benefits of

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the merger. See "The Merger—Description of the Merger Agreement—Termination of the Merger Agreement" beginning on page 162.

Termination of the merger agreement could negatively impact Janus and/or Henderson.

        If the merger agreement is terminated and the merger is not consummated, the ongoing businesses of Janus and Henderson may be adversely affected. Janus's and Henderson's respective businesses may be adversely impacted by the failure to pursue other beneficial opportunities during the pendency of the merger, by the failure to obtain the anticipated benefits of completing the merger, by payment of certain costs relating to the merger, and by the focus of their respective managements on the merger for an extended period of time rather than on normal business operations or opportunities or by the loss of certain senior managers and other key personnel to either or both of Janus and Henderson as a consequence of the merger not completing. The market price of Janus common stock and/or Henderson ordinary shares might decline as a result of any such failures to the extent that the current market prices reflect a market assumption that the merger will be completed. Any of these factors, among others, could have a material impact on the business, prospects, financial condition and results of operations of Janus and/or Henderson.

        In addition, if the merger agreement is terminated under certain circumstances, Janus or Henderson, as applicable, may be required to pay the other party a termination fee of $34,000,000 in cash or to pay the other party's expenses in the amount of up to $10,000,000 in cash, depending on the circumstances surrounding the termination (and in each case subject to certain adjustments that may be required in respect of VAT). See "The Merger—Description of the Merger Agreement—Expenses and Termination Fees."

        Janus or Henderson may also be negatively impacted if the respective companies become subject to litigation related to entering into or failing to consummate the merger, including direct actions by Janus stockholders or Henderson shareholders, as applicable, against the directors and/or officers of Janus or Henderson for breaches of fiduciary duty and derivative actions brought by Janus stockholders or Henderson shareholders in the name of the respective companies.

The investment advisory agreements of the Janus U.S. mutual funds are subject to termination as a result of the merger, and no assurance can be given that approval of new investment advisory agreements will be obtained.

        Under the Investment Company Act, each of the investment advisory agreements for Janus-advised U.S. mutual funds that are registered as an "investment company" under the Investment Company Act automatically terminate in the event of its "assignment", as defined under the Investment Company Act. An assignment may occur under the Investment Company Act if, among other things, Janus undergoes a change of control. In order for Janus to continue to act as an investment adviser to any such Janus-advised U.S. mutual fund, Janus must obtain approval of such fund's board and shareholders of a new investment advisory agreement. Alternatively, in the event that the approval of a new investment advisory agreement by the shareholders of a Janus-advised U.S. mutual fund is not obtained prior to the closing date, Janus may continue to act as investment adviser, subject to certain conditions, for any such Janus-advised U.S. mutual fund for a period of 150 days following an assignment of the applicable investment advisory agreement if such fund's board approves an "interim contract" (within the meaning of Section 15a-4 of the Investment Company Act).

        The merger is expected to result in the assignment of the investment advisory agreements with each such Janus-advised U.S. mutual fund under the Investment Company Act and an assignment of the investment advisory agreements with each of Janus's other clients under the Investment Advisers Act of 1940, as amended, which we refer to as the Advisers Act. Janus is currently in the process of seeking the necessary approvals for new registered fund investment advisory agreements and consents

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from its other clients. It is a condition to closing the merger that Janus receive approval of the boards of trustees or shareholders of Janus-advised U.S. mutual funds of new investment advisory agreements with Janus to take effect at the closing of the merger representing at least 67.5% of the assets under management of those funds as of September 30, 2016. No assurance can be given that Janus will be able to obtain the necessary approvals from the boards and shareholders of the Janus-advised U.S. mutual funds. The decrease in revenue that could result from a failure to obtain such approvals, even if the merger agreement condition is satisfied, could have a material adverse effect on the business, financial condition and results of operations of Janus Henderson.

Janus and Henderson will be subject to business uncertainties while the merger is pending.

        Uncertainty about the closing or effect of the merger may affect the relationship between Henderson and Janus and their respective customers, including through reduced net flows during the pendency of the merger. This uncertainty may also affect the relationship between Henderson and Janus, on the one hand, and their respective business counterparties, on the other hand. Any such impact may have an adverse effect on Janus and/or Henderson, and consequently on the combined company. These uncertainties may cause parties that deal with Henderson and/or Janus to seek to change existing business relationships with them and to delay or defer decisions concerning Henderson or Janus. Changes to existing business relationships, including termination or modification, could negatively affect each of Janus's and Henderson's assets under management, revenue, earnings and cash flow, as well as the market price of Janus's common stock and Henderson's ordinary shares.

Janus and Henderson may face challenges in attracting and retaining key personnel during the pendency of the merger.

        Each of Janus and Henderson is dependent on the experience and industry knowledge of their respective officers, key management personnel and other key employees to operate their businesses and execute their respective business plans. The combined company's success after the merger will depend in part upon the ability of Janus and Henderson to retain key management personnel and other key employees and to attract new management personnel and other key employees. Current and prospective employees of Janus and Henderson may experience uncertainty about their roles within the combined company during and following the merger, which may have an adverse effect on the ability of each of Janus and Henderson to attract or retain key management personnel and other key employees. If key employees depart because of issues related to the uncertainty and difficulty of integration or a desire not to remain with the businesses, the combined company's business following consummation of the merger could be negatively impacted. Accordingly, no assurance can be given that the combined company will be able to attract or retain key management personnel and other key employees of Janus and Henderson to the same extent that Janus and Henderson have previously been able to attract or retain their employees. Adverse effects arising from the pendency of the merger could be exacerbated by any delays in consummation of the merger or termination of the merger agreement.

Janus and Henderson will be subject to certain contractual restrictions while the merger is pending.

        The merger agreement restricts each of Janus and Henderson from making certain acquisitions and divestitures, entering into certain contracts, incurring certain indebtedness and expenditures, repurchasing or issuing securities outside of existing equity awards, and taking other specified actions without the consent of the other party until the earlier of the closing of the merger or the termination of the merger agreement. These restrictions may prevent Janus and/or Henderson from pursuing attractive business opportunities that may arise prior to the closing of the merger and could have the effect of delaying or preventing other strategic transactions. Adverse effects arising from the pendency of the merger could be exacerbated by any delays in consummation of the merger or termination of the

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merger agreement. See "The Merger—Description of the Merger Agreement—Conduct of Business" beginning on page 151.

Third parties may terminate or alter existing contracts or relationships with Janus or Henderson.

        Each of Janus and Henderson has contracts with customers, vendors, distributors, affiliates, landlords, licensors, joint venture partners, and other business partners which may require Janus or Henderson, as applicable, to obtain consent from these other parties in connection with the merger. If these consents cannot be obtained, the counterparties to these contracts and other third parties with which Janus and/or Henderson currently have relationships may have the ability to terminate, reduce the scope of or otherwise materially adversely alter their relationships with either or both parties in anticipation of the merger, or with the combined company following the merger. The pursuit of such rights may result in Janus, Henderson or the combined company suffering a loss of potential future revenue or incurring liabilities in connection with a breach of such agreements and losing rights that are material to its business. Any such disruptions could limit the combined company's ability to achieve the anticipated benefits of the merger. Such disruptions could also result from a delay in the closing of the merger.

Janus and Henderson will incur significant transaction costs in connection with the merger.

        Janus and Henderson have incurred and expect to incur significant non-recurring costs associated with the merger. These costs and expenses include financial advisory, legal, accounting, consulting and other advisory fees and expenses, reorganization and restructuring costs, severance/employee benefit-related expenses, public company filing fees and other regulatory expenses, printing expenses and other related charges. Some of these costs are payable by Janus and Henderson regardless of whether the merger is completed.

Janus directors and executive officers may have interests in the merger different from the interests of Janus stockholders generally.

        Certain of the directors and executive officers of Janus negotiated the terms of the merger agreement, the Janus board approved the merger agreement and the Janus board recommended that Janus stockholders vote in favor of the Janus merger proposal, the Janus compensation proposal, each of the amendment proposals and the Janus adjournment proposal. Janus directors and executive officers have certain financial interests in the merger that may be different from, or in addition to, or in conflict with, those of Janus stockholders generally. These interests include the continued service of certain of Janus's current directors and executive officers as directors and executive officers of Janus Henderson following consummation of the merger, the treatment in the merger of Janus Options, Janus RSU Awards, Janus PSU Awards, Janus Restricted Share Awards, Janus MFU Awards, change-in-control and severance agreements, certain deferred compensation payments and other rights held by Janus directors and executive officers, and the indemnification of former Janus directors and executive officers by Janus Henderson.

        The Janus board was aware of and considered these potential interests, among other matters, in evaluating and negotiating the merger agreement, in determining that the merger agreement and the transactions contemplated thereby were advisable and fair to and in the best interests of the Janus stockholders, and in recommending to you that you vote to approve the Janus merger proposal, the Janus compensation proposal, each of the amendment proposals and the Janus adjournment proposal. Janus stockholders should be aware of these interests when they consider recommendations of the Janus board that they vote in favor of the Janus merger proposal, the Janus compensation proposal, each of the amendment proposals and the Janus adjournment proposal. The interests of Janus directors and executive officers are described in more detail in the section of this proxy statement/prospectus

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entitled "The Merger—Interests of Janus Directors and Executive Officers in the Merger" beginning on page 122.

Existing Janus stockholders will have a reduced ownership and voting interest in, and will exercise less influence over management of, the combined company after the merger than they did with respect to Janus prior to the merger.

        Janus stockholders currently have the right to vote in the election of the Janus board, and on other matters affecting Janus. Upon the closing of the merger, each Janus stockholder who receives Janus Henderson ordinary shares in the merger will become a shareholder of the combined company with a percentage ownership of, and voting interest in, the combined company that is smaller than such stockholder's percentage ownership of, and voting interest in, Janus immediately prior to the merger. Assuming fully diluted equity capitalization of each of Janus and Henderson as of the date the merger agreement was signed, immediately following the closing of the merger, the former Janus stockholders, as a group, will own approximately 43%, of the combined company. Accordingly, Janus stockholders will have less influence on the management and policies of the combined company than they now have on the management and policies of Janus.

Janus Henderson ordinary shares to be received by Janus stockholders in the merger will have rights that differ from the shares of Janus common stock.

        Upon closing of the merger, Janus stockholders will no longer be stockholders of Janus, but will instead be shareholders of Janus Henderson. The rights of former Janus stockholders who become Janus Henderson shareholders will be governed by the Janus Henderson Amended Memorandum and the Janus Henderson Amended Articles, which will be adopted, as of the effective time, in the form of Annex B to this proxy statement/prospectus. The rights associated with Janus Henderson ordinary shares are different from the rights associated with shares of Janus common stock. See "Comparison of Rights of Holders of Janus Henderson Ordinary Shares and Shares of Janus Common Stock" beginning on page 274.

The merger agreement contains provisions that may discourage other companies from trying to enter into a strategic transaction with either Janus or Henderson for greater consideration.

        Notwithstanding that such provisions are to be disregarded in respect of both parties to the extent that the U.K. Panel on Takeovers and Mergers determines that they are prohibited by Rule 21.2 of the City Code, certain provisions of the merger agreement may discourage third parties from submitting business combination proposals to Janus or Henderson during the pendency of the merger agreement that might have otherwise resulted in greater value to Janus stockholders or Henderson shareholders, as applicable, than the merger. These provisions include a general prohibition on each company, its respective controlled affiliates, directors, officer employees and representatives, from soliciting, initiating or knowingly encouraging, or, subject to certain exceptions, entering into discussions with any third party regarding any alternative transactions, subject to limited exceptions. In addition, Dai-ichi, Janus's largest shareholder, has committed to vote its shares of Janus's common stock in favor of the merger. This may discourage a third party from pursuing a strategic transaction with Janus.

        If, in certain permitted circumstances, either the Janus board or Henderson board (i) withdraws, qualifies or modifies, or proposes publicly to withdraw, qualify or modify, or fails to make, in each case in any manner adverse to the other party, its approval or recommendation of the Janus required stockholder approval or the Henderson required shareholder approvals, as applicable, or (ii) approves or recommends, or proposes publicly to approve or recommend, any alternative transaction, Janus or Henderson, as applicable, will still be required to submit the merger to a vote of its stockholders or shareholders, as applicable, at their respective special meetings unless the merger agreement is earlier terminated by the other party in accordance with its terms. For further information, please see the

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section entitled "The Merger—Description of the Merger Agreement—Changes in Board Recommendations" beginning on page 155.

        In addition, Janus or Henderson, as the case may be, must pay to the other party a termination fee equal to $34,000,000 in immediately available funds pursuant to the merger agreement, upon termination of the merger agreement under the following circumstances:

        In addition, if either Janus or Henderson terminates the merger agreement in the event the Janus required stockholder approval (in the case of a termination by Henderson) or the Henderson required shareholder approvals (in the case of a termination by Janus) are not obtained, the party whose stockholders or shareholders, as applicable, failed to provide the requisite approval is required to pay the other party's expenses up to an amount equal to $10,000,000. The expense reimbursement is credited against any termination fee payable as described above. For further information, please see the section entitled "The Merger—Description of the Merger Agreement—Expenses and Termination Fees" beginning on page 163.

        If the merger agreement is terminated and either Henderson or Janus determines to seek another strategic transaction, Henderson or Janus, as applicable, may not be able to negotiate a transaction on terms comparable to, or more favorable than, the terms of the merger agreement.

The market price of the combined company's ordinary shares may be volatile, and holders of the combined company's ordinary shares could lose a significant portion of their investment due to drops in the market price of the combined company's ordinary shares following closing of the merger.

        The market price of the combined company's ordinary shares may be volatile following closing of the merger, and shareholders may not be able to resell their Janus Henderson ordinary shares at or above their value at the effective time due to fluctuations in the market price, including changes in price caused by factors unrelated to the combined company's operating performance or prospects.

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        For a discussion of specific factors that may have a significant effect on the market price for the combined company's ordinary shares please see "—Risks Related to the Combined Business of Janus and Henderson" beginning on page 50 and "—Risks Related to the Business Combination" beginning on page 67.

The opinion of Janus's financial advisor will not be updated to reflect changes in circumstances between the signing of the merger agreement on October 3, 2016 and the closing of the merger.

        Janus has not obtained an updated opinion from its financial advisor as of the date of this proxy statement/prospectus, and Janus does not anticipate asking its financial advisor to update its opinion. Changes in the operations and prospects of Janus or Henderson, general market and economic conditions and other factors that may be beyond the control of Janus or Henderson, and on which Janus's financial advisor's opinion was based, may significantly alter the prices of the shares of Janus common stock or Henderson ordinary shares by the time the merger is completed. The opinion does not speak as of the time the merger will be completed or as of any date other than the date of the opinion. Because Janus's financial advisor will not be updating its opinion, which was issued in connection with the signing of the merger agreement on October 3, 2016, the opinion will not address the fairness of the merger consideration from a financial point of view at the time the merger is completed. The Janus board's recommendation that Janus stockholders vote "FOR" the Janus merger proposal, the Janus compensation proposal, each of the amendment proposals and the Janus adjournment proposal, however, is made as of the date of this proxy statement/prospectus. For a description of the opinion that Janus received from its financial advisor, please refer to "The Merger—Opinion of Janus's Financial Advisor" beginning on page 113.

Janus stockholders will not be entitled to appraisal rights in the merger.

        Appraisal rights are statutory rights that, if applicable under law, enable stockholders to dissent from an extraordinary transaction, such as a merger, and to demand that the corporation pay the fair value for their shares as determined by a court in a judicial proceeding instead of receiving the consideration offered to stockholders in connection with the extraordinary transaction.

        Under DGCL, which is applicable to Janus as a Delaware corporation, stockholders do not have appraisal rights if the shares of stock they hold, as of the record date for determination of stockholders entitled to vote at the meeting of stockholders to act upon a merger, are either (i) listed on a national securities exchange or (ii) held of record by more than 2,000 holders. Notwithstanding the foregoing, appraisal rights are available if stockholders are required by the terms of the merger agreement to accept for their shares anything other than (a) shares of stock of the surviving corporation, (b) shares of stock of another corporation that will either be listed on a national securities exchange or held of record by more than 2,000 holders, (c) cash instead of fractional shares or (d) any combination of clauses (a)-(c).

        Because Janus common stock is listed on the NYSE, a national securities exchange, and is expected to continue to be so listed on the record date for the Janus special meeting, and because Janus stockholders will receive Janus Henderson ordinary shares in the merger, which are expected to be listed on the NYSE upon the effective time, Janus stockholders will not be entitled to appraisal rights in the merger with respect to their shares of Janus common stock.

There has been no prior public market for Janus Henderson ordinary shares on the NYSE, and an active market for such securities may not develop or be sustained and trading prices may vary.

        Upon closing of the merger the Janus Henderson ordinary shares will be registered with the SEC and Henderson intends to apply for the Janus Henderson ordinary shares to be listed on the NYSE, and will commence trading on the NYSE on a conditional "when issued" basis, subject to the official

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notice of issuance, following closing of the merger. Although Henderson ordinary shares are currently listed and admitted to trading on the LSE, prior to closing of the merger there will be no public market for Janus Henderson ordinary shares on the NYSE. Upon listing and trading on the NYSE, there can be no assurance that an active market for Janus Henderson ordinary shares will develop or be sustained if it does develop. The failure of an active and liquid trading market to develop would likely have a material adverse effect on the value of the Janus Henderson ordinary shares.

Risks Related to Being a Jersey, Channel Islands Company Listing Ordinary Shares

Janus Henderson's ordinary shares will be issued under the laws of Jersey, Channel Islands, which may not provide the level of legal certainty and transparency afforded by incorporation in a U.S. state.

        Henderson is organized under the laws of Jersey, Channel Islands, a British crown dependency that is an island located off the coast of Normandy, France. Jersey is not a member of the European Union. Jersey, Channel Islands legislation regarding companies is largely based on English corporate law principles. However, there can be no assurance that the laws of Jersey, Channel Islands, will not change in the future or that it will serve to protect investors in a similar fashion afforded under corporate law principles in the U.S., which could adversely affect the rights of investors.

U.S. shareholders may not be able to enforce civil liabilities against Janus Henderson.

        At present, none of Henderson's directors and officers are residents of the U.S. Following consummation of the merger, certain of Janus Henderson's directors and executive officers will not be residents of the U.S. A substantial portion of the assets of such persons are located outside the U.S. As a result, it may not be possible for investors to effect service of process within the U.S. upon such persons.

        Judgments of U.S. courts may not be directly enforceable outside of the U.S. and the enforcement of judgments of U.S. courts outside of the U.S. may be subject to limitations. Investors may also have difficulties pursuing an original action brought in a court in a jurisdiction outside the U.S. for liabilities under the securities laws of the U.S.

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THE COMPANIES

Janus

Janus Capital Group Inc.

Janus Capital Group Inc.
151 Detroit Street
Denver, CO 80206
United States of America
Telephone: +1 (303) 333-3963

        Janus Capital Group Inc., a Delaware corporation, provides investment management, administration, distribution and related services to financial advisors, individuals and institutional clients through mutual funds, separate accounts, other pooled investment vehicles, exchange-traded products and subadvised relationships (collectively referred to as investment products) in both domestic and international markets. Over the last several years, Janus has expanded its business to become a more diversified manager with increased investment product offerings and distribution capabilities. Janus provides investment management competencies across a range of disciplines, including fundamental U.S. and global equities (growth and value), mathematical equities, fixed income and alternatives, through its subsidiaries, Janus Capital Management LLC, INTECH Investment Management LLC and Perkins Investment Management LLC. As of December 31, 2016, Janus's assets under management totaled $196.8 billion for mutual fund shareholders, clients and institutions around the globe.

        Shares of Janus common stock are listed on the NYSE under the symbol "JNS".

        Additional information about Janus and its subsidiaries is included in documents incorporated by reference in this proxy statement/prospectus. See "Where You Can Find More Information" beginning on page 300.

Henderson

Henderson Group plc

201 Bishopsgate
EC2M 3AE
United Kingdom
Telephone: +44 (0) 20 7818-1818

        Henderson Group plc, a company incorporated and registered in Jersey, Channel Islands, is an independent global asset manager, specializing in active investment across all major asset classes. It is a client-focused global business with over 1,000 employees worldwide, and assets under management of £101.0 billion as of December 31, 2016. Henderson has operations in the U.K., Continental Europe, North America, Latin America, Asia and Australia. Henderson focuses on active fund management by investment managers with unique individual perspectives, who are free to implement their own investment views, within a strong risk management framework.

        Henderson manages a broad range of actively managed investment products for institutional and retail investors across five capabilities: European Equities, Global Equities, Global Fixed Income, Multi-Asset, and Alternatives.

        Additional information about Henderson is included in the section entitled "Business of Henderson" beginning on page 176.

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Merger Sub

Horizon Orbit Corp.

c/o Henderson Group plc
201 Bishopsgate
EC2M 3AE
United Kingdom
Telephone: +44 (0) 20 7818-1818

        Horizon Orbit Corp., which we refer to as Merger Sub, is a Delaware corporation directly and wholly owned by Henderson that was formed on September 23, 2016. To date, Merger Sub has not conducted any activities other than those incidental to its formation. Pursuant to the merger agreement, Merger Sub will be merged with and into Janus, with Janus surviving the merger as a direct and wholly owned subsidiary of Henderson.

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THE JANUS SPECIAL MEETING

General

        This section contains information about the Janus special meeting that has been called to consider and vote on the Janus merger proposal, the Janus compensation proposal, the amendment proposals and the Janus adjournment proposal. This proxy statement/prospectus is being furnished to Janus stockholders in connection with the solicitation of proxies by the Janus board for use at the Janus special meeting and any postponements or adjournments of such special meeting. This proxy statement/prospectus provides Janus stockholders with information about the Janus special meeting and should be read carefully in its entirety.

Date, Time and Place

        The Janus special meeting will be held at the JW Marriott Hotel, 150 Clayton Lane, Denver, Colorado, on April 25, 2017, at 10:00 a.m. (local time).

Purpose of the Janus Special Meeting

        At the Janus special meeting, Janus stockholders will be asked to vote on the following proposals:

        You should carefully read this proxy statement/prospectus in its entirety for more detailed information concerning the transaction and the proposals to be voted on at the Janus special meeting.

Recommendation of the Janus Board

        After careful consideration, the Janus board, on October 1, 2016, unanimously (a) approved the merger agreement and determined that entering into the merger agreement and consummating the transactions contemplated thereby, including the merger, are advisable and fair to, and in the best interests of, Janus and its stockholders; (b) authorized and approved the execution, delivery and performance of the merger agreement by Janus and approved the merger; and (c) recommended the adoption of the merger agreement by the Janus stockholders and directed that the merger agreement be submitted for consideration by the Janus stockholders at the Janus special meeting.

The Janus board unanimously recommends that the Janus stockholders vote:

        "FOR" the Janus merger proposal;

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        "FOR" the Janus compensation proposal;

        "FOR" each of the amendment proposals; and

        "FOR" the Janus adjournment proposal.

Record Date; Stockholders Entitled to Vote

        Only holders of record of shares of Janus common stock at the close of business on March 15, 2017 the record date for voting at the Janus special meeting will be entitled to notice of, and to vote at, the Janus special meeting or any adjournments or postponements thereof. As of the close of business on March 15, 2017, there were 184,297,796 shares of Janus common stock issued and outstanding and entitled to vote at the Janus special meeting, including 36,382,545 shares of Janus common stock held by Dai-ichi. A list of stockholders of record entitled to vote at the Janus special meeting shall be open to any stockholder for any purpose relevant to such meeting for ten days before the Janus special meeting, during normal business hours, at 151 Detroit Street, Denver, Colorado 80206.

Shares and Voting of Janus Directors and Executive Officers

        As of the close of business on March 15, 2017, approximately 2.23% of the issued and outstanding shares of Janus common stock (including Janus Restricted Share Awards entitled to vote) were held by Janus directors and executive officers and their affiliates. We currently expect that Janus directors and executive officers will vote their shares of Janus common stock in favor of the above-listed proposals, although none of them has entered into any agreements obligating him or her to do so.

Quorum

        A quorum of stockholders is necessary to transact business at the Janus special meeting. In order to take any action at the Janus special meeting, a majority of Janus's outstanding shares of common stock as of the record date must be present in person or represented by proxy and entitled to vote at the Janus special meeting, or any adjournment or postponement thereof. The inspectors intend to treat as "present" for these purposes stockholders who have submitted properly executed or transmitted proxies that are marked "abstain." The inspectors will also treat as "present" at the Janus special meeting shares held in "street name" by brokers that are voted on at least one proposal to come before the Janus special meeting. In the event that a quorum is not present, or if there are insufficient votes to adopt the merger agreement at the time of the Janus special meeting, it is expected that the Janus special meeting will be adjourned to solicit additional proxies.

Required Vote

        Proposal 1: Vote on the Janus merger proposal.    The votes cast "FOR" this proposal must represent a majority of all outstanding shares of Janus common stock entitled to vote thereon.

        Proposal 2: Advisory vote on the Janus compensation proposal.    The affirmative vote of a majority of the shares of Janus common stock represented at the Janus special meeting and entitled to vote thereon is required to approve the Janus compensation proposal.

        Proposals 3 through 7: Advisory vote on the amendment proposals.    The affirmative vote of a majority of the shares of Janus common stock represented at the Janus special meeting and entitled to vote thereon is required to approve each of the amendment proposals.

        Proposal 8: Vote on the Janus adjournment proposal.    The affirmative vote of a majority of the shares of Janus common stock represented at the Janus special meeting and entitled to vote thereon is required to approve the Janus adjournment proposal.

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        Under the NYSE rules, if you hold your shares of Janus common stock in "street name," your broker, nominee or intermediary may not vote your shares without instructions from you on non-routine matters. None of the proposals to be voted on at the Janus special meeting are routine matters. Therefore, without your voting instructions, your broker or other nominee may not vote your shares on any of Proposals 1 through 7 at the Janus special meeting.

        Broker non-votes will have the same effect as a vote "AGAINST" Proposal 1 and will have no effect on Proposals 2 through 7 (assuming a quorum is present). However, because none of the proposals to be voted on at the Janus special meeting are routine matters for which brokers may have discretionary authority to vote, Janus does not expect any broker non-votes at the Janus special meeting.

Abstentions and Broker Non-Votes

        A "broker non-vote" occurs on an item when (i) a bank, broker, nominee, intermediary or other holder of record holding shares for a beneficial owner does not vote on a particular proposal because the broker does not have discretionary authority to vote on that particular proposal without receiving voting instructions from the beneficial owner of the shares, and (ii) the beneficial owner fails to provide the bank, broker, nominee, intermediary or other holder of record with such instructions. Under the current rules for the NYSE, brokers do not have discretionary authority to vote on "non-routine" proposals, including the Janus merger proposal (Proposal 1), the vote, on an advisory basis, on the Janus compensation proposal (Proposal 2), the vote, on an advisory basis, on the amendment proposals (Proposals 3 through 7) and the Janus adjournment proposal (Proposal 8). Because none of the proposals to be voted on at the Janus special meeting are routine matters for which brokers may have discretionary authority to vote, Janus does not expect any broker non-votes at the Janus special meeting. If you hold your shares in street name, it is critical that you cast your vote by instructing your bank, broker or other nominee on how to vote if you want your vote to be counted at the Janus special meeting. The NYSE rules governing brokers' discretionary authority will not permit brokers to exercise discretionary authority regarding any of the proposals to be voted on at the Janus special meeting.

        If you are a Janus stockholder and you mark your proxy or voting instructions to abstain, it will have the effect of a vote "AGAINST" the Janus merger proposal, the Janus compensation proposal, each of the amendment proposals and the Janus adjournment proposal. If you are a Janus stockholder and you fail to instruct your broker or nominee to vote, it will have the effect of a vote "AGAINST" the Janus merger proposal but will have no effect on the Janus compensation proposal, the amendment proposals and the Janus adjournment proposal, assuming a quorum is present.

How to Vote

Voting by Proxy

        If you hold shares of Janus common stock in your name as a holder of record, which we refer to as the registered stockholder, you can vote your shares by one of the following methods:

        By Internet—You may submit a proxy electronically via the Internet at www.proxyvote.com until 11:59 p.m. EDT on April 24, 2017. Please have your proxy card in hand when you log on to the website. The Internet procedures are designed to authenticate a stockholder's identity to allow stockholders to vote their shares and confirm that their instructions have been properly recorded. Internet voting facilities for stockholders of record are available 24 hours a day. Voting via the Internet authorizes the named proxies to vote your shares in the same manner as if you had submitted a validly executed proxy card.

        By Telephone—You may submit a proxy by telephone, toll-free, at 1-800-690-6903 until 11:59 p.m. EDT on April 24, 2017. Please have your proxy card in hand when you call. The telephone voting

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procedures are designed to authenticate a stockholder's identity to allow stockholders to vote their shares and confirm that their instructions have been properly recorded. Voting by telephone authorizes the named proxies to vote your shares in the same manner as if you had submitted a validly executed proxy card.

        By Mail—You may complete, sign and date the proxy card and return it so that it is received by 11:59 p.m. EDT on April 24, 2017.

        If your shares of Janus common stock are held in a stock brokerage account or by a bank, or other holder of record, you are considered the "beneficial owner" of shares held in street name. As the beneficial owner, you have the right to direct your broker, bank, or other registered stockholder on how to vote your shares by using the voting instruction form included in the mailing or by following their instructions for voting by telephone or on the Internet.

Voting at the Janus special meeting

        Attendance at the Janus special meeting is limited to Janus stockholders on the record date and their proxies. Please indicate on the proxy card if you plan to attend the Janus special meeting. You will need proof of ownership to enter the Janus special meeting. If you are a beneficial owner of shares of Janus common stock and you plan to attend the Janus special meeting, you must present proof, such as a bank or brokerage account statement, of your ownership of Janus common stock as of the record date to be admitted to the Janus special meeting.

        If you are a registered stockholder, representatives of Janus will confirm your stockholder status at the Janus special meeting. You must present a form of personal identification to be admitted to the Janus special meeting. NO CAMERAS, RECORDING EQUIPMENT, ELECTRONIC DEVICES, BAGS, BRIEFCASES, PACKAGES, OR SIMILAR ITEMS WILL BE PERMITTED AT THE JANUS SPECIAL MEETING.

        If you vote by proxy and also attend the Janus special meeting, you do not need to vote again at the Janus special meeting unless you wish to change your vote. Even if you plan to attend the Janus special meeting, we strongly urge you to vote in advance by proxy by signing and dating the enclosed proxy card and returning it in the postage-paid envelope provided or by voting via the Internet or by telephone by following the instructions provided on the enclosed proxy card and below. Submitting your proxy prior to the Janus special meeting does not limit your right to vote in person at the Janus special meeting if you decide to do so. If you wish to vote in person at the Janus special meeting, we will pass out written ballots for such purpose as requested; however, if you are a beneficial owner, you must obtain a legal proxy from your broker, bank, or other holder of record and bring it to the Janus special meeting to vote in person at the Janus special meeting.

        Janus stockholders should not send in their stock certificates with their proxy cards.    Janus stockholders will be sent materials for exchanging shares of Janus common stock shortly after the closing of the transaction.

Voting of Proxies

        A proxy card is enclosed for your use. Janus requests that you mark, sign and date the accompanying proxy and return it promptly in the enclosed postage-paid envelope. When the accompanying proxy is returned properly executed, the shares of Janus common stock represented by it will be voted at the Janus special meeting or any adjournment thereof in accordance with the instructions contained in the proxy. If no specific instructions are given by you when you execute your voting form, as explained on the form, your shares will be voted as recommended by the Janus board as stated in this proxy statement/prospectus, specifically "FOR" the Janus merger proposal, "FOR" the

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Janus compensation proposal, "FOR" each of the amendment proposals, and "FOR" the Janus adjournment proposal.

        At the date hereof, Janus's management has no knowledge of any business that will be presented for consideration at the Janus special meeting and which would be required to be set forth in this proxy statement/prospectus or the related Janus proxy card other than the matters set forth in Janus's Notice of Special Meeting of Stockholders. If any other matter is properly presented at the Janus special meeting for consideration, it is intended that the persons named in the enclosed form of proxy and acting thereunder will vote in accordance with their best judgment on such matter and as the Janus board may recommend.

        Your vote is important. Accordingly, please mark, sign, date and return the enclosed proxy card whether or not you plan to attend the Janus special meeting in person.

How Proxies Are Counted

        All shares of Janus common stock represented by properly executed proxies received in time for the Janus special meeting will be voted at the meeting in the manner specified by the Janus stockholder giving those proxies. Properly executed proxies that do not contain voting instructions with respect to the Janus merger proposal, the Janus compensation proposal, the amendment proposals or the Janus adjournment proposal will be voted as recommended by the Janus board as stated in this proxy statement/prospectus, specifically "FOR" the Janus merger proposal, "FOR" the Janus compensation proposal, "FOR" each of the amendment proposals and "FOR" the Janus adjournment proposal.

Voting of Janus Common Stock Held in Street Name

        If you hold shares of Janus common stock through a broker, bank or other nominee, you may instruct your broker, bank or other nominee to vote your shares of Janus common stock by following the instructions that the broker, bank or other nominee provides to you with these materials. Most brokers offer the ability for stockholders to submit voting instructions by mail by completing a voting instruction card, by telephone and via the Internet. Your broker, bank or other nominee may have an earlier deadline by which you must provide instructions to it as to how to vote your shares, so you should read carefully the materials provided to you by your broker, bank or other nominee. If you do not provide voting instructions to your broker, bank or other nominee, your Janus shares will not be voted on any proposal as your broker, bank or other nominee does not have discretionary authority to vote on any of the proposals to be voted on at the Janus special meeting. We urge you to instruct your broker or other nominee how to vote your shares by following those instructions.

        Broker non-votes are counted for the purpose of determining the presence or absence of a quorum for purposes of the Janus special meeting but are not considered votes cast. With respect to the Janus merger proposal, a broker non-vote will have the effect of a vote "AGAINST" the proposal. With respect to the Janus compensation proposal, the amendment proposals and the Janus adjournment proposal, a broker non-vote will have no effect on such proposals. Because none of the proposals to be voted on at the Janus special meeting are routine matters for which brokers may have discretionary authority to vote, Janus does not expect any broker non-votes at the Janus special meeting.

        If you hold shares of Janus common stock in the name of your broker, bank, or other nominee and wish to vote your shares of Janus common stock in person at the Janus special meeting, you must obtain a legal proxy from your broker or nominee and present it to the inspector of election with your ballot when you vote at the Janus special meeting.

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Voting by Employees Participating in the Employee Stock Ownership Plan and the Kansas City Southern 401(k) Plan

        Each participant in the Janus ESOP and the KCS 401(k) Plan may instruct the respective trustees of these plans on how to vote the shares of Janus common stock held on behalf of the participant under such plans. The trustee of each plan must receive your voting instructions for the common stock allocated to your Janus ESOP or KCS 401(k) Plan account before April 21, 2017. If the trustee for the Janus ESOP or the KCS 401(k) Plan does not receive your voting instructions before April 21, 2017, it will vote those shares, subject to the requirements of the Employee Retirement Income Security Act of 1974, as amended, in the same proportion as the voting instructions that it receives from other Janus ESOP or KCS 401(k) Plan account holders (as applicable).

        On March 15, 2017, there were 1,173,928.265 outstanding Janus shares in the Janus 401(k) and Employee Stock Ownership Plan.

Revocability of Proxies and Changes to a Janus Stockholders' Vote

        If you are a registered stockholder, you may change your vote or revoke your proxy at any time before it is exercised at the Janus special meeting. You may do this in one of four ways:

        Your attendance in and of itself will not revoke any proxy.

        If your shares of Janus common stock are held in street name, you should follow the instructions of your broker regarding the revocation of proxies.

        Once voting on a particular matter is completed at the Janus special meeting, a Janus stockholder will not be able to revoke its proxy or change its vote as to that matter.

        All shares of Janus common stock represented by valid proxies that Janus receives through this solicitation and that are not revoked will be voted in accordance with the instructions on the proxy card. If a Janus stockholder makes no specifications on its proxy card as to how it should want its shares of Janus common stock voted before signing and returning it, such proxy will be voted as recommended by the Janus board as stated in this proxy statement/prospectus, specifically "FOR" the Janus merger proposal, "FOR" the Janus compensation proposal, "FOR" each of the amendment proposals and "FOR" the Janus adjournment proposal.

Tabulation of Votes

        The Janus board has appointed David W. Grawemeyer, Amy J. Stefonick and Broadridge Financial Services to serve as the inspectors of election for the Janus special meeting. The inspectors of election will, among other matters, determine the number of shares of Janus common stock represented at the Janus special meeting to confirm the existence of a quorum, determine the validity of all proxies and ballots and certify the results of voting on all proposals submitted to the Janus stockholders.

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Solicitation of Proxies

        Janus is soliciting proxies to provide an opportunity to all Janus stockholders to vote on agenda items, whether or not the stockholders are able to attend the Janus special meeting or an adjournment or postponement thereof. Janus will bear the entire cost of soliciting proxies from its stockholders, except that Janus and Henderson have agreed to each pay one half of the costs and expenses of filing, printing and mailing this proxy statement/prospectus and all filing and other similar fees payable to the SEC in connection with this proxy statement/prospectus. In addition to the solicitation of proxies by mail, Janus will request that banks, brokers and other record holders send proxies and proxy material to the beneficial owners of shares of Janus common stock and secure their voting instructions, if necessary. Janus will reimburse the record holders on request for their reasonable expenses in taking those actions.

        Janus has also made arrangements with Georgeson LLC to assist in soliciting proxies and in communicating with Janus stockholders. Proxies also may be solicited on behalf of Janus in person, by mail, by telephone, by facsimile, by messenger, via the Internet or by other means of communication, including electronic communication, or by Janus directors, officers and employees in person, by mail, by telephone, by facsimile, via the Internet or by other means of communication, including electronic communication. Directors, officers and employees of Janus will not be specially compensated for their services or solicitation in this regard.

Adjournments

        If the Janus special meeting is postponed or adjourned, your proxy will still be valid and may be voted at the postponed or adjourned meeting in the manner described in this proxy statement/prospectus. You will still be able to revoke your proxy until it was voted at the postponed or adjourned meeting.

        If a quorum is not present or represented, a meeting of Janus stockholders may be adjourned from time to time by the vote of shares of Janus common stock having a majority of the votes of the shares of Janus common stock represented at such meeting until a quorum is present.

        If a quorum is present at the Janus special meeting but there are not sufficient votes at the time of the Janus special meeting to approve the Janus merger proposal, then Janus stockholders may be asked to vote on the Janus adjournment proposal. No notices of an adjourned meeting need be given if the time and place to which the meeting is adjourned are announced at the meeting at which the adjournment is taken, unless the Janus board sets a new record date for such meeting, in which case a notice of the adjourned meeting will be given to each Janus stockholder of record entitled to vote at the meeting. At any subsequent reconvening of the Janus special meeting at which a quorum is present, any business may be transacted that might have been transacted at the original meeting and all proxies will be voted in the same manner as they would have been voted at the original convening of the Janus special meeting, except for any proxies that have been effectively revoked or withdrawn prior to the time the proxy is voted at the reconvened meeting.

Assistance

        If you need assistance in completing your proxy card or have questions regarding the Janus special meeting, please contact Georgeson LLC, the proxy solicitation agent for Janus, at 888-565-5423.

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THE MERGER

Effects of the Merger

        At the effective time, Merger Sub will be merged with and into Janus, with Janus surviving the merger as a direct and wholly owned subsidiary of Henderson.

        Subject to the terms and conditions set forth in the merger agreement, Janus stockholders will have the right to receive, with respect to each share of Janus common stock they hold at the effective time, 4.7190 Henderson ordinary shares, with cash paid in lieu of fractional Henderson ordinary shares based on then prevailing market prices, subject to the following adjustments. Effective immediately prior to the closing of the merger, subject to approval by the Henderson shareholders at the Henderson shareholder meeting, Henderson will implement the share consolidation at a ratio of one Janus Henderson ordinary share (or CDI, as applicable) for every 10 Henderson ordinary shares (or CDIs, as applicable) outstanding (so that at closing of the merger each Janus stockholder will receive 0.4719 Janus Henderson ordinary shares for each share of Janus common stock). In addition, subject to approval by the Henderson shareholders at the Henderson shareholder meeting, effective upon the date of the Henderson shareholder meeting, the par value of Henderson ordinary shares will be redenominated from pounds sterling into U.S. dollars. Following the redenomination, subject to approval by the Henderson shareholders at the Henderson shareholder meeting, upon completion of certain registration procedures with the Jersey Registrar of Companies, the par value of Henderson ordinary shares will be reduced to ensure that the par value is a round number. In addition, each share of common stock of Merger Sub, par value $0.01 per share, issued and outstanding immediately prior to the effective time will be cancelled and, in exchange for the cancellation and the funding of the merger consideration by Henderson, Janus, as the surviving corporation in the merger, will issue an equivalent number of fully paid and non-assessable shares of common stock, par value $0.01 per share, all of which shares will be held by Henderson, and which will constitute the only outstanding shares of common stock of Janus, as the surviving corporation, immediately following the effective time.

        The merger agreement does not contain any provision that would adjust the exchange ratio based on fluctuations in the market value of either the Janus common stock or Henderson ordinary shares or currency exchange rates. Because of this, the implied value of consideration to the Janus stockholders may fluctuate between now and closing of the merger. The value of the consideration to Janus stockholders will depend on the market value of Henderson ordinary shares at the time the merger is completed and on currency exchange rates. The merger agreement provides that the merger consideration will be adjusted appropriately to reflect the effect of any stock/share split, reverse stock split, share consolidation, share subdivision, share bonus issue or stock/share dividend (including any dividend or distribution of securities convertible into the Henderson ordinary shares or Janus common stock, as applicable), reorganization, recapitalization, reclassification, combination, exchange of shares or other like change with respect to the number of shares of Henderson ordinary shares or Janus common stock issued and outstanding after October 3, 2016 and prior to the effective time.

Background of the Merger

        The management and board of directors of Janus regularly reviews and discusses the performance, risks, strategy, prospects and competitive position of Janus, as well as business opportunities available to Janus. In addition, the management and board of directors of Janus from time to time reviews and evaluates the possibility of pursuing various strategic alternatives and relationships as part of Janus's ongoing efforts to strengthen its overall business and enhance value for its stockholders, taking into account economic, regulatory, competitive and other conditions.

        On February 10, 2016, Richard Weil, Chief Executive Officer of Janus, was in London to visit Janus's London offices. Representatives of Bank of America Merrill Lynch, which we refer to as BAML, had suggested that they arrange an introduction between Mr. Weil and Andrew J. Formica,

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Chief Executive Officer of Henderson, while Mr. Weil was in London. On February 10, 2016, Mr. Weil and Mr. Formica met and discussed the asset management industry generally and their respective businesses, though they did not have any substantive discussions regarding any strategic transaction involving Janus and Henderson.

        On March 8, 2016, Mr. Weil and Mr. Formica spoke by telephone to discuss certain follow-up items from their February meeting. They also discussed whether a strategic transaction between Henderson and Janus would be worth considering, and each agreed to consider the possibility with their respective boards.

        On April 7, 2016, Mr. Weil and Mr. Formica spoke by telephone to continue discussions on the asset management industry generally, and their respective businesses, as well as the possibility of exploring a potential business combination of Janus and Henderson. They did not discuss the structure or any specific terms of such a transaction, but each of them agreed to consider the matter further, as well as further discussions on this topic.

        On April 8, 2016, during a regularly scheduled call between Mr. Weil and Glenn Schafer, Chairman of the Janus board, Mr. Weil informed Mr. Schafer that he had spoken to Mr. Formica, that in that conversation the possibility of exploring a potential business combination of Janus and Henderson had been raised, and that Mr. Weil and Mr. Formica had agreed to continue these exploratory discussions.

        On April 16, 2016, Mr. Weil met with a representative of Loeb Spencer House Partners, which we refer to as Loeb Spencer House, to discuss the asset management industry generally and Janus's business strategy. Mr. Weil and the representative from Loeb Spencer House Partners also discussed Mr. Weil's previous discussions with Mr. Formica regarding a potential business combination of Janus and Henderson and potential next steps in the event Janus decided to explore such a combination.

        On April 19, 2016, Janus and Henderson entered into a mutual confidentiality and nondisclosure agreement to facilitate the sharing of preliminary non-public information about their respective businesses. From this date through October 2, 2016, representatives of Janus and Henderson conducted a due diligence review of the other party, including numerous telephonic and in person meetings to discuss their respective businesses and operations.

        On April 21 and 22, 2016, the Janus board held its regularly scheduled quarterly meeting in person. Members of Janus management were present at the meeting to provide a general business update to the Janus board. During the meeting, Mr. Weil informed the Janus board of his exploratory discussions with Mr. Formica regarding a preliminary evaluation of the potential merits of a potential business combination with Henderson.

        On May 4, 2016, Mr. Formica and other members of Henderson's senior management travelled to Janus's headquarters in Denver, Colorado to meet with Mr. Weil and other members of Janus's senior management to discuss the strategic rationale and merits and challenges of a business combination of Janus and Henderson. They did not discuss the possible structure or any specific terms of such a combination, but agreed to consider further discussions if it appeared that a combination could be attractive to both companies. Also on May 4, 2016, Mr. Weil called a representative of Loeb Spencer House to discuss the possibility of Loeb Spencer House advising Janus in evaluating a potential business combination with Henderson. Pursuant to an engagement letter, dated June 16, 2016, Janus and Loeb Spencer House confirmed Loeb Spencer House's engagement as Janus's financial advisor with respect to the potential business combination between Janus and Henderson.

        In early May 2016, Mr. Weil, other members of Janus management and a representative of Loeb Spencer House had several calls with members of Henderson management and a representative of BAML, financial advisor to Henderson, to discuss the process for exploring the merits of a potential business combination between Janus and Henderson. These discussions remained preliminary in nature

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and no specific terms were discussed, however it was noted that any potential combination between Janus and Henderson would be structured as a "merger of equals". The parties agreed to continue discussions to evaluate one another's businesses so as to determine whether a potential business combination would be worth pursuing.

        On May 9, 2016, Mr. Weil and Mr. Formica discussed by telephone the feedback they had received from their respective management teams on the Denver meetings that took place on May 4, 2016, and the subsequent telephone calls, and decided to continue their discussions relating to the potential combination.

        On May 18, 2016, Mr. Weil and Mr. Formica spoke by telephone to discuss the ongoing due diligence process.

        On May 19, 2016, Mr. Formica and other members of Henderson management met with a representative from Loeb Spencer House to continue discussions regarding a potential business combination between Janus and Henderson.

        On May 20, 2016, on a regularly scheduled call between Mr. Weil and Mr. Schafer, Mr. Weil updated Mr. Schafer on his discussions with Mr. Formica regarding the consideration of a potential business combination with Henderson. Mr. Weil noted that these conversations continued to be exploratory in nature and that he would continue to provide Mr. Schafer and the rest of the Janus board with updates after his further discussions with Mr. Formica.

        On May 31, 2016, Richard Gillingwater, Chairman of the Henderson board, called the Chairman of the FCA to inform him of Henderson's preliminary discussions with Janus regarding a potential business combination.

        On June 1, 2016, Mr. Weil and Mr. Formica discussed by telephone their desire to continue discussions regarding a potential business combination. On this call, they discussed the appropriate corporate process to continue discussions and to exchange views as to potential transaction structure and other key deal terms and requirements (including by establishing deal teams on each side), such as potential governance and management structures and the appropriate way to approach Dai-ichi, Janus's largest stockholder and an important strategic partner, about the potential business combination.

        In early June 2016, Janus engaged Skadden, Arps, Slate, Meagher & Flom LLP and affiliates, which we refer to as Skadden, as outside counsel to Janus, to assist Janus in its evaluation of a potential transaction.

        On June 16, 2016, Mr. Weil and Bruce Koepfgen, President of Janus, met with members of management of Dai-ichi in Tokyo to provide Dai-ichi with an update on the preliminary discussions between Janus and Henderson regarding a potential business combination between Janus and Henderson. The parties discussed the potential benefits of a transaction to Janus and Dai-ichi and also discussed the important role the support of Dai-ichi would play in any such transaction.

        On June 21, 2016, the Janus board held a meeting by telephone to discuss a potential business combination with Henderson. Also in attendance were Janus management and representatives of Loeb Spencer House and Skadden. Mr. Weil provided an overview of his preliminary discussions with Mr. Formica and of the preliminary business rationale of the potential transaction. Mr. Weil noted that the preliminary business rationale included, among other things, compatible employee cultures of Janus and Henderson, the highly complementary distribution strengths of Janus and Henderson, the limited overlap in product offerings between Janus and Henderson and the potential benefits of a larger and more diversified platform to execute a global growth strategy and to withstand fluctuations of various global markets as a result of the scale of the combined company. Jennifer McPeek, the Chief Financial Officer of Janus, also discussed preliminary estimates of potential synergies that might be realized in connection with a business combination with Henderson. A representative from Loeb Spencer House

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presented to the Janus board an overview of certain transaction structuring issues and terms that would need to be addressed in any combination of the kind under consideration, including issues related to a stock-for-stock transaction (such as the exchange ratio and governance matters). The representative from Loeb Spencer House Partners also presented, on a preliminary basis, certain valuation and other financial analyses and parameters that would customarily be applicable to the potential combination. Throughout the meeting, the Janus board asked numerous questions about the topics presented and discussion ensued. The topics discussed included the need for further analysis and discussion regarding the impact of a transaction on stockholders and clients, the cultural and strategic fit with Henderson in a potential transaction and the challenges and risks in any potential transaction. At the conclusion of the meeting, the Janus board agreed with the recommendation of Janus management to continue discussions with Henderson to explore the potential merits of a business combination.

        Later in the day on June 21, 2016, Mr. Weil and Mr. Formica discussed by telephone a plan for members of Henderson management to travel to Janus's headquarters in Denver, Colorado to meet members of Janus management.

        On June 24, 2016, Mr. Weil and Mr. Formica discussed by telephone the next steps to continue to evaluate a potential business combination between the two firms. Both Mr. Weil and Mr. Formica each expressed interest in continuing their discussions with a view towards determining if a potential business combination would be in the best interest of their respective shareholders and stockholders.

        Later in the day on June 24, 2016, Janus and Henderson entered into a new confidentiality and nondisclosure agreement that superseded the prior confidentiality and nondisclosure agreement entered into on April 19, 2016. This confidentiality agreement contained a mutual standstill and employee non-solicit and no-hire restrictions.

        On June 26, 2016, members of Janus and Henderson management (and their respective financial advisors) spoke by telephone to discuss the process for the commencement of a more detailed financial due diligence review of each party by the other party.

        On June 30 2016, while on a previously scheduled trip to London, Mr. Weil met with Mr. Formica and other members of Henderson senior management to discuss the potential cultural and business fit of the two firms, the firms' respective businesses and strategies, potential headquarters, the potential for a co-chief executive officer structure and other governance and management matters.

        Later in the day on June 30, 2016, Mr. Weil and Mr. Formica met to discuss the general outline of a transaction and confirmed the fact that if each party determined to pursue a transaction, it would be structured as a "merger of equals". They also discussed generally other matters related to a possible transaction, including the structure of the board of the combined company and the potential for a co-chief executive officer structure for the combined company.

        On July 5, 2016, Mr. Weil and Mr. Formica spoke by telephone to discuss the current status of their respective evaluations of a potential business combination. Mr. Weil and Mr. Formica agreed that their respective management teams and boards of directors were supportive of continuing discussions beyond the preliminary stages. Mr. Weil and Mr. Formica also discussed preparing a preliminary non-binding term sheet to outline some general terms of a potential transaction that would need to be addressed.

        On July 10, 2016, a representative of BAML, Henderson's financial advisor, sent to representatives of Loeb Spencer House, Janus's financial advisor, an initial draft of a preliminary non-binding term sheet setting forth Henderson's proposal for certain transaction terms related to structure, governance and similar matters.

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        On July 11, 2016, Mr. Gillingwater and Mr. Schafer discussed by telephone issues related to the executive leadership, board numbers and composition, and the importance of the participation of Dai-ichi in the prospective merger.

        On July 13, 2016, Mr. Weil and Mr. Formica spoke by telephone to discuss a number of matters, including the possible co-chief executive officer structure, integration and outstanding due diligence issues.

        On July 14, 2016, Ms. McPeek and Roger Thompson, the Chief Financial Officer of Henderson, met in New York to discuss potential transaction structures, certain financial matters and financial due diligence.

        On July 18, 2016, members of Janus and Henderson management (and Loeb, BAML and Centerview Partners UK LLP, which we refer to as Centerview, financial advisor to Henderson) met by telephone to discuss the business due diligence process and certain integration considerations. Also, on July 18, 2016, members of Janus and Henderson management and representatives of Freshfields Bruckhaus Deringer LLP, outside legal counsel to Henderson, which we refer to as Freshfields, and Skadden met in person at the offices of Skadden to discuss the process for initiating the reciprocal legal due diligence review.

        On July 19, 2016, a representative of Loeb Spencer House sent to BAML a draft of a preliminary non-binding term sheet setting forth Janus's proposal for certain transaction terms related to structure, governance and similar matters.

        On July 18 and 19, 2016, members of Janus and Henderson management (and Loeb and BAML) met in person at the offices of Skadden to discuss their respective investment products and teams and strategies.

        On July 20, 2016, the Janus board held its regularly scheduled quarterly meeting in person. At that meeting, Janus management provided a general business update and overview of Janus's proposed business strategy for achieving growing market share and organic growth. In addition, Mr. Weil provided an update on the potential business combination with Henderson, including an update on the strategic rationale and potential benefits of the transaction and certain preliminary transaction terms that were being discussed between Janus and Henderson. The Janus board asked questions about a variety of the topics presented and discussion ensued. The topics discussed included, among other things, the potential impact of Brexit on Henderson and on the potential transaction, governance matters, the strategic rationale of the transaction and valuation. At the conclusion of the meeting, the Janus board agreed with the recommendation of Janus management to continue discussions with Henderson regarding a potential business combination.

        On July 21, 2016, the compensation committee of the Janus board held its regularly scheduled quarterly meeting in person to discuss the entry by Janus into change in control agreements with certain members of Janus's executive committee and certain other Janus employees in the event that Janus entered into a transaction with Henderson.

        On July 25, 2016, Mr. Weil and Mr. Formica met in New York City to continue discussions regarding the potential business combination. At this meeting, they discussed the draft term sheet and a number of important matters that would need to be addressed in connection with any such transaction, including the compensation structures of their respective firms and of the combined company, the cultural fit of their respective firms, the co-chief executive officer structure, the composition of the executive committee of the combined company, the name of the combined company, the structure of the board of the combined company, potential synergies, strategic priorities, regulatory considerations, the Dai-ichi relationship and the potential methodology to be used to determine the exchange ratio. They did not reach agreement on these matters as the purpose of the meeting was to identify key

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considerations both parties would need to consider further if the parties continued their discussions regarding a business combination.

        Mr. Weil and Mr. Formica, together with their respective financial advisors, engaged in various discussions regarding the methodology to calculate the exchange ratio through September 27, 2016, when the parties agreed on such methodology. During the course of these discussions, the parties discussed a number of factors and considerations deemed to be relevant to determining a mutually acceptable methodology to determine the exchange ratio in the event the parties decided to pursue a transaction, including, among others, the trading relationship of Janus and Henderson shares over time, the relative business prospects of Janus and Henderson, equitable sharing between Janus and Henderson shareholders of the synergies expected to be created as a result of a potential transaction and any premium to be reflected in the exchange ratio.

        On July 29, 2016, members of Janus management and members of Henderson management discussed by telephone certain compensation matters, including the potential need to harmonize compensation structures for the combined company, in the event the potential business combination discussions progressed further, as well as the status of the financial due diligence review by both Janus and Henderson.

        On August 12, 2016, Mr. Weil and Mr. Formica discussed by telephone the status of their respective reviews of the potential business combination. They discussed the status of the ongoing due diligence reviews, as well as a number of the potential transaction terms previously discussed at their July 25th meeting, including the name of the combined company, corporate branding, the executive committee and management of the combined company and the Dai-ichi relationship.

        Also on August 12, 2016, Mr. Weil spoke individually by telephone with several members of the Janus board to provide an update regarding the status of discussions with Henderson. Janus management also provided the Janus board with a written update on the status and strategic merits of a potential combination with Henderson.

        On August 16, 2016, members of Janus and Henderson management met by telephone to discuss potential synergies in connection with a potential business combination.

        On August 17, 2016, Loeb Spencer House and BAML met to discuss Janus's and Henderson's desire to enter into a voting agreement with Dai-ichi and to ensure the continued significant ownership stake of Dai-ichi in the combined company and other potential terms related to the potential business combination.

        On August 18, 2016, Janus sent Dai-ichi a draft of the amended and restated investment agreement providing for the continued investment by Dai-ichi in the combined company. Thereafter, during the period between August 18, 2016 and October 2, 2016, representatives of (i) Janus and Skadden, (ii) Henderson and Freshfields and (iii) Dai-ichi and its counsel Davis Polk & Wardwell LLP exchanged a number of drafts of the Dai-ichi agreements and engaged in negotiations regarding the terms and conditions of the Dai-ichi agreements.

        On August 19, 2016, Mr. Weil and Mr. Formica spoke by telephone to discuss the status of their respective reviews of the potential business combination, including the name of the combined company, possible governance and management structures, stock exchange listing of the shares of the combined company, the ongoing due diligence review process and the process for furthering discussions on the key transaction matters, among other topics.

        On August 23, 2016, Mr. Weil and Mr. Formica travelled to Japan to meet together with members of Dai-ichi management to discuss the potential business combination. At that meeting, Mr. Formica provided Dai-ichi with a presentation on the Henderson business and strategy, and the parties discussed

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various matters related to the potential business combination, including the continuation of the Dai-ichi strategic relationship and the support of Dai-ichi for the potential business combination.

        On August 24, 25 and 26, 2016, members of Janus and Henderson management held a series of meetings at Janus's headquarters in Denver, Colorado to discuss potential post-transaction organizational structures for the combined company. At those meetings, members of Janus and Henderson management discussed estimates of synergies (including cost synergies and revenue synergies), the cultural and strategic fit of Janus and Henderson (including a similar strategic focus on active management and client service and an emphasis on collaborative and fundamental research driven investment processes), compensation structures and the finance, distribution, information technology, legal and other operations of their respective businesses, among other matters. Representatives of Loeb Spencer House and BAML joined certain of these meetings.

        During the course of the day on August 26, 2016, Mr. Weil, Mr. Formica, Mr. Schafer, Mr. Gillingwater and Lawrence Kochard, a member of the Janus board and Chair of the Compensation Committee, had a series of meeting at Janus's headquarters in Denver, Colorado with each other and members of Janus and Henderson management to discuss a wide range of topics, including the business and strategy of Janus and Henderson, the strategic rationale and benefits of a transaction and possible governance and management structures of the combined company.

        Later in the day on August 26, 2016, Mr. Weil, Mr. Formica, Mr. Schafer, Mr. Kochard and Mr. Gillingwater met to further discuss the board composition and management structure of the combined company.

        In late August 2016, Mr. Koepfgen met with members of Henderson management at Henderson's headquarters in London to discuss various matters related to the potential transaction, including feedback from the Henderson board, Janus's and Henderson's respective U.S. mutual fund complexes, corporate branding, the stock exchange listing of the shares of the combined company, the Dai-ichi relationship and possible governance and management structures.

        On September 1, 2016, Mr. Weil and Mr. Formica discussed by telephone the status of their respective evaluations of the potential business combination, including their respective due diligence reviews, their current positions on a number of the key transaction terms, including the name of the combined company and the governance and management structure of the combined company, and preparations for their upcoming board meetings. Mr. Weil and Mr. Formica also continued their prior discussions regarding the appropriate methodology for determining the exchange ratio.

        On September 8, 2016, the Janus board held a special meeting by telephone to discuss the status of the ongoing discussions with Henderson regarding a potential combination with Henderson. Representatives of Loeb Spencer House and Skadden were in attendance. Janus management provided an update on the potential business combination with Henderson, including a discussion of the strategic rationale of the transaction and a comparison of the respective opportunities and risks associated with pursuing Janus's existing strategy as a standalone firm, as well as the current status of discussions with Henderson on certain key transaction terms. The Janus board asked a variety of questions relevant to the presentation and discussion ensued. A representative of Loeb Spencer House, made a presentation to the Janus board addressing certain financial matters, including considerations applicable to the determination of the exchange ratio in stock for stock transactions. These considerations included, among others, the trading relationship of Janus and Henderson shares over time, the relative business prospects of Janus and Henderson, equitable sharing between Janus and Henderson shareholders of the synergies expected to be created as a result of the potential transaction and any premium to be reflected in the exchange ratio. The Janus board then discussed the merits and risks of the proposed transaction, as well as the absence of any other attractive and reasonably available strategic transactions. Lastly, Mr. Weil provided an update on certain key open transaction terms, including the exchange ratio and the name of the combined company. After further discussion, the Janus board

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agreed that management should continue discussions with Henderson regarding a potential business combination to determine whether a combination would be value-enhancing to Janus's stockholders and, if so, whether mutually agreeable terms could be reached.

        On September 9, 2016, Mr. Weil and Mr. Formica had a telephone call with other members of Henderson's senior management team to discuss feedback from Janus's board meeting and the FCA and the Australian business of the combined group.

        In mid-September 2016, Mr. Weil and members of Janus management met with Mr. Formica and members of Henderson management at Henderson's headquarters in London over several days to discuss the potential transaction. The meetings involved topics relating to the potential business combination, including finance, investor relations, human resources, corporate development and the status of the business due diligence review.

        On September 13, 2016, Skadden received an initial draft of the merger agreement prepared by Henderson and Freshfields reflecting Henderson's proposed terms and on September 22, 2016, Skadden received an initial draft of the Janus Henderson Amended Memorandum and Janus Henderson Amended Articles prepared by Henderson and Freshfields reflecting Henderson's proposed changes to Henderson's existing organizational documents. During the period between September 13, 2016 and October 2, 2016, representatives of Janus and Skadden, on the one hand, and representatives of Henderson and Freshfields, on the other hand, exchanged numerous drafts of the merger agreement and the Janus Henderson Amended Memorandum and Janus Henderson Amended Articles and engaged in negotiations regarding the terms and conditions of the merger agreement and the provisions of the Janus Henderson Amended Memorandum and Janus Henderson Amended Articles. During this period, Janus, Henderson and their respective advisors continued their respective due diligence reviews.

        On September 16, 2016, Mr. Weil and Mr. Formica discussed by telephone employee contracts and change of control issues.

        On September 19, 2016, members of Dai-ichi management, including Tatsusaburo Yamamoto, Dai-ichi's representative on the Janus board met with Mr. Formica and members of Henderson management in London to discuss, among other things, Henderson's culture, strategic vision and investment products.

        On September 21, 2016, Mr. Weil and Mr. Formica discussed by telephone the status of the potential combination and the key open business terms, including the exchange ratio, governance structure and the name of the combined company. No agreement was reached on the open business terms and they agreed to speak at a later date to continue the discussion.

        On September 23, 2016, the Janus board held a special meeting by telephone to discuss the potential combination with Henderson. Janus management and representatives of Loeb Spencer House and Skadden were in attendance. A representative of Loeb Spencer House discussed certain financial parameters related to the potential business combination with Henderson, including the recent relative share price performance of Janus and Henderson, the relative market values of Janus and Henderson on a currency adjusted basis and an exchange ratio analysis. Representatives of Skadden discussed the material terms of the draft merger agreement. Mr. Koepfgen reviewed the current status and terms of the draft Dai-ichi agreements, and Mr. Weil provided an update on current negotiations with Henderson on certain key open terms, including the exchange ratio and name of the combined company. The Janus board asked a variety of questions relevant to the presentations and discussion ensued. The Janus board agreed that it was in the best interest of Janus and its stockholders for management to continue to engage in discussions with Henderson with a view to determining whether agreement on mutually satisfactory terms could be reached.

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        Also on September 23, 2016 Mr. Weil and Mr. Formica discussed by telephone feedback from the Henderson board, the Dai-ichi relationship, exchange ratio, brand, potential headquarters and the draft merger agreement, among other topics.

        On September 26, 2016, Mr. Weil and Mr. Formica, along with representatives of Loeb Spencer House and BAML, participated in a conference call to discuss certain material open items in the draft merger agreement, including the methodology to calculate the exchange ratio and the name of the combined company. Certain items remained open at the conclusion of this call.

        On the morning of September 27, 2016, Mr. Weil and Mr. Formica, along with representatives of Loeb Spencer House and BAML, again participated in a conference call to discuss the items that remained open at the conclusion of the previous day's call. Again, such items were not resolved, and the parties recessed to consider potential compromises. Later on that same day, after further negotiations by telephone, Mr. Weil and Mr. Formica agreed in principle on a methodology to calculate the exchange ratio and the name of the combined company. The agreed methodology to calculate the exchange ratio was primarily based upon the average of the daily volume weighted average price (which we refer to as VWAP) in USD for each share of Janus common stock and each Henderson ordinary share over the 30 trading days (excluding U.S. and U.K. holidays) from August 18, 2016 to September 30, 2016. The VWAP for Janus common stock was $14.3173 and the VWAP for Henderson ordinary shares was $3.1098. This period was selected as the most relevant period for measuring the relative prices of Janus common stock and Henderson ordinary shares taking into account the long-term trading relationship of the securities, the impact of Brexit and the "merger of equals" structure of the transaction. Mr. Weil and Mr. Formica then agreed to an adjustment of 2.5% to the resulting exchange ratio in favor of the Janus stockholders representing an equitable sharing of the expected incremental shareholder value to be created from the expected synergies from the transaction. As part of the negotiation and agreement on the exchange ratio, the parties did not attempt to produce a particular ownership split of the combined company. After application of the 2.5% adjustment, the ratio of the VWAP for Janus common stock to the VWAP for Henderson ordinary shares produced the exchange ratio of 4.7190, which is expected to result in Henderson shareholders and Janus stockholders owning approximately 57% and 43%, respectively, of Janus Henderson immediately following closing of the merger. On September 30, 2016, the last trading day prior to the public announcement of the merger, the implied value of the merger consideration payable in respect of each share of Janus common stock was 1,094.81 pence, or $14.20 in dollar equivalent.

        On September 27, 2016, Skadden sent to Freshfields a list of key material open items in the draft merger agreement, which included items related to governance, employee compensation and benefits, and conditions to closing of the merger, among others.

        On September 28, 2016, representatives of Skadden and representatives of Freshfields discussed by telephone the Skadden list of key material open items relating to the draft merger agreement and the Dai-ichi agreements. After the call, Freshfields sent to Skadden an annotated list to reflect the discussions from the call.

        On September 29, 2016, representatives of Skadden and representatives of Freshfields discussed by telephone Janus's and Henderson's respective positions on the remaining key material open items in the draft merger agreement.

        Also on September 29, 2016, members of Janus management and members of Henderson management discussed by telephone the communication plan regarding the announcement of the business combination assuming that an agreement could be reached.

        Also on September 29, 2016, Mr. Weil and Mr. Formica discussed by telephone the remaining key material open items in the draft merger agreement.

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        Also, in the evening of September 29, 2016, Skadden sent to Freshfields a revised draft of the merger agreement to reflect Janus's position in relation to the key material open items. Over the next three days, Skadden and Freshfields and their respective clients worked to resolve the remaining open items in the draft merger agreement and the Dai-ichi agreements.

        On September 30, 2016, Mr. Weil and Mr. Formica discussed by telephone feedback from the respective Janus and Henderson board meetings and the briefing of the investment managers of their respective businesses.

        On October 1, 2016, the compensation committee of the Janus board held a special meeting in person to discuss certain change in control agreements to be entered into by Janus and certain Janus employees in connection with the business combination with Henderson and to discuss a severance and transaction-related retention and bonus program to be implemented by Janus. The compensation committee approved the severance and transaction-related retention and bonus program and recommended to the Janus board the approval of these programs.

        Later on October 1, 2016, the Janus board held a special meeting in person to discuss and consider the business combination with Henderson. The Janus board was joined at the meeting by representatives of Janus management, as well as representatives from Loeb Spencer House and Skadden. Mr. Weil provided an update on the resolution of the open issues in the merger agreement, including the agreement reached with Henderson on the combined company name and exchange ratio. Representatives from Skadden provided an update on revisions to the proposed merger agreement. Janus board members asked questions and discussion ensued. Following such discussion, representatives from Loeb Spencer House presented their updated financial analysis of the proposed combination. Loeb Spencer House rendered to the Janus board its oral opinion, confirmed by delivery of a written opinion dated October 1, 2016, to the effect that as of that date, and based upon and subject to the factors and assumptions set forth in the written opinion, the exchange ratio set forth in the merger agreement was fair from a financial point of view to holders of shares of Janus common stock (other than Janus or any wholly-owned subsidiary of Janus or Henderson and its affiliates). Loeb Spencer House's opinion is more fully described in the section of this proxy statement/prospectus entitled "The Merger Agreement—Opinion of Janus's Financial Advisor" beginning on page 113 of this proxy statement/prospectus and the full text of the written opinion of Loeb Spencer House, which sets forth the assumptions and limitations in such opinion, is attached as Annex C hereto. Thereafter, the Janus board unanimously determined that it was advisable and in the best interests of Janus and its stockholders to enter into the merger agreement and the transactions contemplated by the merger agreement, and the board unanimously approved the merger agreement and the transactions contemplated by the merger agreement. In addition, the board unanimously approved the Dai-ichi agreements.

        On October 2, 2016, Janus and Henderson finalized the merger agreement, the Janus Henderson Amended Memorandum, the Janus Henderson Amended Articles and the Dai-ichi agreements.

        On October 3, 2016, the merger agreement was executed and delivered by Janus, Henderson and Merger Sub and the Dai-ichi agreements were executed and delivered by Janus, Henderson and Dai-ichi (as applicable).

        On the morning of October 3, 2016, prior to market openings in London and the U.S., Janus and Henderson issued a joint press release announcing the execution of the merger agreement.

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Janus's Reasons for the Merger; Recommendation of the Janus Board

        At its meeting on October 1, 2016, the Janus board unanimously determined that the merger agreement, the voting agreement and the amended investment and cooperation agreement and the transactions contemplated thereby, including the merger, are advisable, fair to, and in the best interests of, Janus and its stockholders, and adopted the merger agreement, the voting agreement and the amended investment and cooperation agreement. The Janus board unanimously recommends that the Janus stockholders vote "FOR" each of the Janus merger proposal, the Janus compensation proposal, the amendment proposals and the Janus adjournment proposal.

        In evaluating the merger agreement, the Janus board reviewed and discussed a significant amount of information and consulted with and received the advice of Janus's senior management and its legal and financial advisors. In reaching its decision, the Janus board considered a number of factors, including, but not limited to, the following factors which the Janus board believed supported its decision to adopt and enter into the merger agreement and its recommendation that Janus stockholders vote "FOR" each of the Janus merger proposal, the Janus compensation proposal, the amendment proposals and the Janus adjournment proposal:

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        These beliefs are based in part on the following factors considered by the Janus board:

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        The Janus board weighed these advantages and opportunities against a number of risks and potential negative factors concerning the merger agreement and the merger, including:

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        The foregoing discussion of the factors considered by the Janus board is not intended to be exhaustive, but rather includes the principal factors considered by the Janus board. In view of the wide variety of factors considered in connection with its evaluation of the merger and the complexity of these matters, the Janus board did not find it useful and did not attempt to quantify or assign any relative or specific weights to the various factors that it considered in reaching its determination to approve the merger agreement and to make its recommendations to Janus stockholders. In addition, individual members of the Janus board may have given differing weights to different factors. The Janus board conducted an overall review of the factors described above, including thorough discussions with Janus management and outside legal and financial advisors.

        The Janus board concluded that the uncertainties, risks and potentially negative factors relevant to the transaction were outweighed by the potential benefits that it expected Janus and the Janus stockholders would achieve as a result of the transaction.

        In considering the recommendation of the Janus board to approve the Janus merger proposal, Janus stockholders should be aware that Janus directors may have interests in the merger that are different from, or in addition to, those of Janus stockholders generally. For additional information, see the section entitled "—Interests of Janus Directors and Executive Officers in the Merger" beginning on page 122 of this proxy statement/prospectus.

        The foregoing discussion is based on assumptions regarding the cost synergies and revenue growth opportunities Janus expects to achieve following the merger. However, these expected cost synergies and revenue growth opportunities may not develop. There can be no assurance that Janus will be able to successfully implement the strategic or operational initiatives that are intended. The explanation of the reasoning of the Janus board and certain information presented in this section are forward-looking in nature and, therefore, the information should be read in light of the factors discussed in the section entitled "Cautionary Statement Regarding Forward-Looking Statements" beginning on page 49 of this proxy statement/prospectus.

Henderson's Reasons for the Merger

Strategic Considerations.

        The Henderson board considers that the merger is expected to provide a number of significant strategic opportunities and outcomes, including the following:

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Other Factors Considered by the Henderson Board.

        In addition to the strategic factors described above, the Henderson board considered the following additional factors:

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        The Henderson board weighed these advantages and opportunities against a number of other factors identified in its deliberations that weighed negatively against the merger, including:

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        The foregoing discussion of the factors considered by the Henderson board is not exhaustive, but rather includes the principal factors considered by the Henderson board in connection with its deliberations related to the merger. In view of the wide variety of factors considered in connection with its evaluation of the merger and the complexity of these matters, the Henderson board did not find it useful to, and did not attempt to, quantify or assign any relative or specific weights to the various factors that it considered in reaching its determination to approve the merger agreement and to make its recommendations to Henderson shareholders. In addition, individual members of the Henderson board may have given differing weights to different factors. The Henderson board conducted an overall review of the factors described above, including thorough discussions with Henderson's management and outside legal and financial advisors.

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        The foregoing discussion is based on assumptions regarding the cost synergies and revenue growth opportunities Henderson expects to achieve following the merger. However, these expected cost synergies and revenue growth opportunities may not develop. There can be no assurance that Henderson will be able to successfully implement the strategic or operational initiatives that are intended. The explanation of the reasoning of the Henderson board and certain information presented in this section are forward-looking in nature and, therefore, the information should be read in light of the factors discussed in the section entitled "Cautionary Statement Regarding Forward-Looking Statements" beginning on page 49 of this proxy statement/prospectus.

Certain Estimated Synergies

        As a result of the detailed and collaborative integration planning work undertaken since announcement of the merger, Henderson and Janus have been able both to further validate the initial cost synergy estimate and identify areas with further potential for cost synergies. Accordingly, Henderson and Janus continue to believe that Janus Henderson will be able to achieve at least $110 million of recurring annual run rate pre-tax net cost synergies, representing approximately 19% of Janus Henderson's underlying EBITDA (based on the EBITDA for the year ended December 31, 2016 for each of Henderson ($275.3 million) and Janus ($310.9 million)).

        The work undertaken by the integration teams has led Henderson and Janus to believe that the delivery of these synergies will be accelerated, with significant elements of the cost synergy plan already in progress. Janus Henderson is expected to realize approximately $80 million of net cost synergies by the end of the first 12 months following closing of the merger on a run rate basis, with the remainder expected to be fully executed on a run rate basis within three years of closing.

        The announced cost synergies are expected to be realized as follows:

        It is estimated that the realization of these net cost synergies and other integration-related activities will result in non-recurring costs of up to $185 million, of which an estimated $125 million has already been incurred or will be incurred by the end of the 2017 financial year and the balance within three years post closing of the merger.

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Basis of belief

        The analysis undertaken by Henderson and Janus in quantifying the potential synergies has been reviewed by external accountants and is informed by Henderson and Janus managements' industry experience as well as their experience of executing and integrating past acquisitions. The analysis is based on the Henderson business and Janus business on a stand-alone basis and their detailed plans to integrate the two businesses globally.

        The potential synergies have been calculated based on the latest available management information, consistent with that contained in Henderson's and Janus's financial information for the period ended December 31, 2016.

        In arriving at the estimate and phasing of the potential synergies and non-recurring costs Henderson and Janus have made a number of key assumptions, including:

        The estimated cost synergies identified above reflect both the beneficial elements and relevant costs of achieving them. The estimated synergies are contingent on the merger being completed and the expected benefits of the merger being realized. They assume that no restrictions, terms or other conditions will be imposed in connection with the receipt of any governmental, regulatory or other approvals or consents necessary in connection with completion of the merger. The estimated synergies would not be achievable on a stand-alone basis.

        See the sections above titled "Cautionary Statement Regarding Forward-Looking Statements" beginning on page 49 of this proxy statement/prospectus and "Risk Factors—Risks Related to the Business Combination—The combined company may fail to realize the anticipated benefits of the merger" beginning on page 67 of this proxy statement/prospectus for further information regarding the uncertainties and factors associated with realizing the synergies in connection with the merger.

Henderson Management Forecast

        Henderson does not as a matter of course make public forecasts as to future performance, revenues, earnings or other results due to the unpredictability and uncertainty of the underlying assumptions and estimates. However, in connection with the review of the merger, Henderson's management prepared and provided to Janus, certain illustrative non-public, unaudited internal financial information regarding Henderson's future operations for the fiscal years ending December 31, 2016 through 2020. This unaudited illustrative financial information, which we refer to as the Henderson Management Forecast, was prepared and provided in September 2016, treating Henderson on a stand-alone basis.

        The Henderson Management Forecast was not prepared for the purpose of public disclosure. However, a summary of the Henderson Management Forecast has been included below to provide Janus stockholders access to this financial information that was furnished to Janus.

        The Henderson Management Forecast was prepared using IFRS accounting policies. The Henderson Management Forecast was not prepared in compliance with U.S. GAAP, the published

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guidelines of the SEC regarding projections and forward-looking statements, the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of prospective financial information, or the guidelines established by the International Accounting Standards Board for preparation and presentation of financial forecasts. In the view of Henderson management, it reflected the best available estimates and judgments at the time the Henderson Management Forecast was prepared taking into account their inherent limitations. The inclusion of the Henderson Management Forecast below is not an indication that Henderson or the Henderson board provided, or currently provides, any assurance that Henderson will achieve (or would have achieved on a standalone basis) the results reflected in the Henderson Management Forecast. The summary of the Henderson Management Forecast is being included in this proxy statement/prospectus because this information was provided by Henderson to Janus, as well as to Janus' financial advisor, for the purposes of considering and evaluating the merger and the merger agreement. The Henderson Management Forecast has been prepared by, and is the responsibility of, Henderson's management. Neither Henderson's independent registered public accounting firm nor any other independent accountant has examined, compiled or performed any procedures with respect to the Henderson Management Forecast, or expressed any opinion or any other form of assurance on such information or its achievability. The independent registered public accounting firm report issued by PricewaterhouseCoopers LLP, London, United Kingdom (PwC) included in this proxy statement/prospectus relates to Henderson's historical financial information. It does not extend to the Henderson Management Forecast and should not be read to do so.

        The Henderson Management Forecast is subjective in many respects and, as a result, subject to interpretation. The Henderson Management Forecast was based on numerous variables and assumptions that are inherently uncertain and may be beyond the control of Henderson's management. Important factors that may affect actual results and cause the Henderson Management Forecast to not be achieved include, but are not limited to, risks and uncertainties relating to Henderson's business (including its ability to achieve strategic goals, objectives and targets over applicable periods), industry performance, general business and economic conditions, and the other factors described under "Cautionary Statement Regarding Forward-Looking Statements" beginning on page 49 of this proxy statement/prospectus. See also "Where you Can Find More Information" and "Risk Factors" beginning on pages 300 and 50, respectively, of this proxy statement/prospectus. The Henderson Management Forecast also reflects assumptions as to certain business decisions that have been or will be subject to change. As a result, actual results are expected to differ materially from the Henderson Management Forecast. Accordingly, there can be no assurance that the Henderson Management Forecast will be realized or that actual results will not be significantly lower or higher than estimated. Portions of the Henderson Management Forecast cover multiple years. Such information also by its nature becomes less predictive with each successive year.

        The Henderson Management Forecast reflects various assumptions and estimates that Henderson management made in good faith for illustrative purposes at the time that the Henderson Management Forecast was prepared, all of which are difficult to predict and many of which are beyond Henderson's control, including, without limitation:

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        These assumptions are inherently uncertain, were made as of the time the prospective financial information was prepared, and will not be reflective of actual results, either now or in the future, in light of changed circumstances, or other developments.

        The 2016 forecasts within the Henderson Management Forecasts have been superseded by actual results and the 2017-20 targets included in the Henderson Management Forecasts do not reflect the view of the Henderson board of directors as of the date hereof as to the future financial performance targets of Henderson. Therefore they are no longer considered to be valid.

        In practice, a number of the assumptions above have already proved to be incorrect, some materially, as a result of various macroeconomic and other external factors (including foreign exchange fluctuations) that have occurred since the date on which the Henderson Management Forecast was prepared.

        The Henderson Management Forecast was also prepared, without giving effect to, and as if Henderson never contemplated, the merger, including the impact of negotiating or executing the merger, the expenses that may be incurred in connection with consummating the merger, the potential synergies that may be achieved by Janus Henderson as a result of the merger, the effect of any business or strategic decision or action that has been or will be taken as a result of the merger agreement having been executed, or the effect of any business or strategic decisions or actions which would likely have been taken if the merger agreement had not been executed but which were instead altered, accelerated, postponed or not taken in anticipation of the merger.

        None of Henderson, Janus or their respective affiliates, advisors, officers, directors or other representatives can provide any assurance that actual results will not differ from the Henderson Management Forecast, and, except as required by applicable securities laws, none of them undertakes any obligation to update, or otherwise revise or reconcile, the Henderson Management Forecast to reflect circumstances existing after the date such forward-looking information was generated or to reflect the occurrence of future events even in the event that any or all of the assumptions underlying the Henderson Management Forecast are shown to be in error. Except as required by applicable securities laws, Henderson does not intend to make publicly available any update or other revision to the Henderson Management Forecast, even in the event that any or all assumptions are shown to be in error. None of Henderson or its affiliates, advisors, officers, directors or representatives has made or makes any representation regarding Henderson's ultimate performance compared to the information contained in the Henderson Management Forecast or that forecast results will be achieved. Henderson has made no representation to Janus, in the merger agreement or otherwise, concerning the Henderson Management Forecast. The Henderson Management Forecast does not take into account any circumstances or events occurring after the date that they were prepared. The inclusion of this information should not be regarded as an indication that the Henderson board of directors, Henderson, or any other recipient of this information considered, or now considers, the Henderson Management Forecast to be material information of Henderson.

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Summary of the Henderson Management Forecast

        The following discussion provides a summary of the Henderson Management Forecast:

Opinion of Janus's Financial Advisor

Loeb Spencer House

        Janus has retained Loeb Spencer House to act as Janus's financial advisor in connection with the merger. Loeb Spencer House Partners was formed in 2015 as a strategic alliance between Loeb Partners Corporation in New York and Spencer House Partners LLP in London to advise financial institutions globally, with a focus on asset management and wealth management. Janus selected Loeb Spencer House to act as Janus's financial advisor in connection with the merger on the basis of the experience of Loeb Spencer House's professionals in transactions similar to the merger and the reputation of those professionals in the investment banking community.

        On October 1, 2016, at a meeting of the board of directors of Janus held to evaluate the merger, Loeb Spencer House rendered its oral opinion to the Janus board, which was confirmed by delivery of a written opinion dated October 1, 2016, that, as of such date and based upon and subject to the factors and assumptions set forth therein, the exchange ratio set forth in the merger agreement was fair from a financial point of view to holders of shares of Janus common stock (other than Janus or any wholly-owned subsidiary of Janus or Henderson and its affiliates).

        The full text of the written opinion of Loeb Spencer House, dated October 1, 2016, which sets forth assumptions made, procedures followed, matters considered and limitations on the review undertaken in connection with the opinion, is attached as Annex C. The following summary of Loeb Spencer House's opinion is qualified in its entirety by reference to the full text of the opinion. Loeb Spencer House provided its opinion for the benefit of the Janus board (in its capacity as such) in connection with its evaluation of the consideration to be paid to holders of shares of Janus common stock in the merger from a financial point of view. Loeb Spencer House's opinion did not address the relative merits of the merger compared to any other transaction or business strategy in which Janus might engage or the merits of the underlying decision by Janus to pursue the merger. The Loeb Spencer House opinion is not intended to be and does not constitute a recommendation as to how any holder of shares of Janus common stock should vote with respect to the merger or any other matter.

        In connection with rendering the opinion described above and performing its related financial analyses, Loeb Spencer House:

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        For purposes of its opinion, Loeb Spencer House assumed and relied upon the accuracy and completeness of information that was publicly available or supplied or otherwise made available to it by Janus or Henderson without independent verification of such information, and assumed no liability therefor. Loeb Spencer House did not conduct any independent valuation or appraisal of any of the assets or liabilities (contingent or otherwise) of Janus or Henderson or concerning the solvency of Janus or Henderson under any applicable laws relating to bankruptcy, insolvency or similar matters, and it was not furnished with any such valuation or appraisal, nor did it make any physical inspection of the properties or assets of Janus or Henderson. With respect to the projected financial and operating data and synergy analyses relating to Janus and Henderson, Loeb Spencer House assumed that such data and analyses had been reasonably prepared on bases reflecting the best currently available estimates and good faith judgments of the respective managements of Janus and Henderson as to the future financial performance of Janus and Henderson, as applicable, under the assumptions stated therein. Loeb Spencer House expressed no view as to any projected financial and operating data or synergies or any judgments, estimates or assumptions on which they were based. Loeb Spencer House relied at the Janus board's direction, without independent verification, upon the assessments of the management of Janus and Henderson as to the future financial and operating performance of Janus and Henderson, and assumed that Janus and Henderson would realize the benefits that each expected to realize from the merger.

        Loeb Spencer House's opinion was necessarily based on economic, legal, monetary, market and other conditions as in effect on, and the information made available to it as of, the date of its opinion. Loeb Spencer House's opinion noted that circumstances or events occurring after the date of its opinion may affect its opinion, and it assumed no responsibility for updating or revising its opinion based on circumstances or events occurring after the date of its opinion. Loeb Spencer House did not express any opinion as to what the price of the Henderson ordinary shares actually will be when issued in the merger or as to the prices at which shares of Janus common stock or Henderson ordinary shares may trade at any time subsequent to the announcement of the merger. Loeb Spencer House was not authorized by the Janus board to solicit, and did not solicit, indications of interest in a possible transaction with Janus from any third party.

        In rendering its opinion, Loeb Spencer House assumed, with the consent of the Janus board, that the merger would be consummated on the terms described in the merger agreement, without any waiver or modification of any material terms or conditions. Representatives of Janus advised Loeb Spencer House, and Loeb Spencer House assumed that the merger agreement, when executed, would

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conform to the draft reviewed by Loeb Spencer House in all material respects. Loeb Spencer House assumed that the representations and warranties made by Janus, Henderson and merger sub in the merger agreement were and will be true and correct in all respects material to its opinion. Loeb Spencer House also assumed, with the consent of the Janus board, that obtaining the necessary governmental, regulatory or third-party approvals and consents for the merger would not result in any delay, limitation, restriction or condition, including any divestiture requirements or amendments or modifications, that would have an adverse effect on Janus, Henderson, the merger or the benefits of the merger to Janus, the holders of Janus common stock or Henderson. Loeb Spencer House's opinion noted that it is not a legal, tax or regulatory advisor. Loeb Spencer House is a financial advisor only and relied upon, without independent verification, the assessment of Janus and its legal, tax and regulatory advisors with respect to legal, tax and regulatory matters. Loeb Spencer House expressed no opinion as to any terms or other aspects (other than the exchange ratio to the extent expressly specified in its opinion) of the merger, including, without limitation, the form or structure of the merger or any agreements or arrangements entered into in connection with, or contemplated by, the merger. Loeb Spencer House expressed no opinion as to the fairness of any consideration paid in connection with the merger to the holders of any other class of securities, creditors or other constituencies of Janus. In addition, Loeb Spencer House expressed no view or opinion as to the fairness of the amount or nature of, or any other matter relating to, the compensation to any officers, directors or employees of any parties to the merger agreement, or class of such persons, relative to the exchange ratio or otherwise.

        The following is a summary of the material financial analyses delivered by Loeb Spencer House to the Janus board in connection with rendering the opinion described above. The following summary, however, does not purport to be a complete description of the financial analyses performed by Loeb Spencer House, nor does the order of analyses described represent relative importance or weight given to those analyses by Loeb Spencer House. Some of the summaries of the financial analyses include information presented in tabular format. The tables must be read together with the full text of each summary and read alone, such tables do not constitute a complete description of Loeb Spencer House' financial analyses. Except as otherwise noted, the following quantitative information, to the extent that it is based on market data, is based on market data as it existed on or before October 1, 2016 and is not necessarily indicative of current market conditions.

Relative Trading Analysis

        Loeb Spencer House reviewed the historical trading prices for the shares of Janus common stock and Henderson ordinary shares and calculated the implied daily exchange ratio for the (i) 30-day period, (ii) 70-day period (from June 24, 2016, the day following the U.K. European Union membership referendum) and (iii) 12-month period, in each case ending September 30, 2016. Based on a comparison of the low and high implied exchange ratios during the 30-day, 70-day and 12-month periods ending September 30, 2016, Loeb Spencer House derived a range of implied exchange ratios of Henderson ordinary shares to one share of Janus common stock of 4.41 to 4.76, 4.41 to 5.34 and 2.94 to 5.34, respectively. The exchange ratio of 4.7190 Henderson ordinary shares (prior to adjustment for the share consolidation) to be received for each share of Janus common stock, as provided for in the merger agreement, was within each of the foregoing ranges.

Market Comparables Analysis

        Loeb Spencer House reviewed and compared certain financial information for Janus to corresponding financial information, ratios and public market multiples for certain publicly held companies that operate in, or are exposed to, businesses similar to those of Janus.

        Selected Publicly Traded Comparable Companies: Janus

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        With respect to the selected companies, the information Loeb Spencer House presented included: (1) the multiple of share price to estimated earnings per share, based on analyst consensus estimates for the calendar year ended 2016 (referred to in this section as the P/E 2016E), the calendar year ended 2017 (referred to in this section as the P/E 2017E) and the calendar year ended 2018 (referred to in this section as the P/E 2018E) and (2) the multiple of enterprise value (calculated as equity value plus non-controlling interest and net debt) to EBITDA (representing earnings before interest, taxes, depreciation and amortization), based on analyst consensus estimates for the calendar year ended 2016 (referred to in this section as the EV/EBITDA 2016E), for the calendar year ended 2017 (referred to in this section as the EV/EBITDA 2017E) and for the calendar year ended 2018 (referred to in this section as the EV/EBITDA 2018E). Estimated financial data for the selected companies was based on the selected companies' filings with the SEC and publicly available analyst consensus estimates that Loeb Spencer House obtained from FactSet Research Systems and Thomson Reuters Eikon.

        Results of this analysis were presented for the selected companies, as indicated in the following table:


Market Comparables Analysis: Selected Companies

 
  P/E 2016E   P/E 2017E   P/E 2018E   EV/EBITDA
2016E
  EV/EBITDA
2017E
  EV/EBITDA
2018E
 

Low

    9.7x     9.6x     8.5x     4.5x     4.9x     4.8x  

High

    21.8x     18.7x     16.9x     12.6x     11.9x     9.7x  

        Having completed the above analysis, Loeb Spencer House, in its judgment, selected a range of relevant multiples for Janus and applied these judgmental ranges to the applicable metrics from the forecast provided by Janus management, which is referred to as the Janus Management Forecast, and

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consensus median estimates to calculate implied valuations. Based on this analysis, Loeb Spencer House estimated the following ranges of implied value per share of Janus common stock:


Market Comparables Analysis: Implied Equity Value Per Janus Share

 
  Janus Management Forecast   Consensus Median Estimates

P/E

  $12.58 - $14.55   $12.47 - $14.42

EV/EBITDA

  $13.36 - $15.04   $13.29 - $14.95

        Loeb Spencer House reviewed and compared certain financial information for Henderson to corresponding financial information, ratios and public market multiples for certain publicly held companies that operate in, or are exposed to, businesses similar to those of Henderson.

        Selected Publicly Traded Comparable Companies: Henderson

        With respect to the selected companies, the information Loeb Spencer House presented included: (1) the P/E 2016E, the P/E 2017E and the P/E 2018E and (2) the EV/EBITDA 2016E, the EV/EBITDA 2017E and the EV/EBITDA 2018E. Estimated financial data for the selected companies was based on the selected companies' public filings and publicly available analyst consensus estimates that Loeb Spencer House obtained from FactSet Research Systems and Thomson Reuters Eikon.

        Results of this analysis were presented for the selected companies, as indicated in the following table:


Market Comparables Analysis: Selected Companies

 
  P/E 2016E   P/E 2017E   P/E 2018E   EV/EBITDA
2016E
  EV/EBITDA
2017E
  EV/EBITDA
2018E
 

Low

    13.2x     8.6x     7.7x     8.0x     5.5x     4.5x  

High

    21.8x     19.5x     17.1x     15.2x     13.5x     12.0x  

        Having completed the above analysis, Loeb Spencer House, in its judgment, selected a range of relevant multiples for Henderson and applied these ranges to the applicable metrics from the forecast provided by the Henderson management, which is referred to as the Henderson Management Forecast, and consensus median estimates to calculate implied valuations. Based on this analysis, Loeb Spencer House estimated the following ranges of implied value of Henderson ordinary share:


Market Comparables Analysis: Implied Equity Value Per Henderson Ordinary Share

 
  Henderson
Management
Forecast
  Consensus
Median
Estimates

P/E

  £2.47 - £2.69   £2.26 - £2.46

EV/EBITDA

  £2.17 - £2.58   £2.05 - £2.43

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        Based on a comparison of the upper and lower limits of these reference ranges of implied value per share of Janus common stock and Henderson ordinary shares (converted to U.S. dollars at the FactSet Research Systems exchange rate on September 30, 2016), Loeb Spencer House derived a range of implied exchange ratios of Henderson ordinary shares to shares of Janus common stock (1) utilizing the Janus Management Forecast and the Henderson Management forecast of (i) 3.59 to 4.42 based on P/E multiples and (ii) 3.98 to 5.32 based on EBITDA multiples; and (2) utilizing consensus median estimates of (i) 3.90 to 4.91 based on P/E multiples and (ii) 4.21 to 5.63 based on EBITDA multiples. The exchange ratio of 4.7190 Henderson ordinary shares to be received for each share of Janus common stock, as provided for in the merger agreement, was within or above each of the foregoing ranges.

        Although the selected companies were used for comparison purposes, no business of any selected company is either identical or directly comparable to either Janus's or Henderson's business. Accordingly, Loeb Spencer House's comparison of selected companies to Janus and Henderson and analysis of the results of such comparisons was not purely mathematical, but instead necessarily involved complex and subjective considerations and judgments concerning differences in financial and operating characteristics and other factors that could affect the relative values of the selected companies.

Discounted Cash Flow Analysis

Janus:

        Janus does not as a matter of course make public forecasts as to future performance, revenues, earnings or other results due to the unpredictability and uncertainty of the underlying assumptions and estimates. However, in connection with the review of the merger, Janus's management prepared certain illustrative non-public, unaudited internal financial information regarding Janus's future operations. This unaudited illustrative financial information, which we refer to as the Janus Management Forecast, was prepared and provided in September 2016, treating Janus on a stand-alone basis. The Janus Management Forecast was not prepared for the purpose of public disclosure. The Janus Management Forecast was prepared using U.S. GAAP accounting policies. The Janus Management Forecast was not prepared with a view toward public disclosure or with a view towards complying with the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of prospective financial information, but in the view of Janus management, it reflected the best available estimates and judgments at the time the Janus Management Forecast was prepared taking into account their inherent limitations. The inclusion of the Janus Management Forecast below is not an indication that Janus or the Janus board considered, or currently considers, such information to be a predictor of actual future results. The summary of the Janus Management Forecast is being included in this proxy statement/prospectus because this information was provided by Janus to Janus's financial advisor, for the purposes of considering and evaluating the merger and the merger agreement. Neither Janus's independent registered public accounting firm nor any other independent accountant has examined, compiled or performed any procedures with respect to the accompanying financial information, or expressed any opinion or any other form of assurance on such information or its achievability and they assume no responsibility for and have disclaimed any association with such information. The independent registered public accounting firm report issued by Deloitte & Touche LLP, Denver, Colorado, incorporated by reference in this proxy statement/prospectus relates to Janus's historical financial information. It does not extend to the Janus Management Forecast and should not be read to do so.

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        Loeb Spencer House conducted a discounted cash flow analysis for Janus based on the Janus Management Forecast by:

        These analyses resulted in the following reference range of implied equity value per share of Janus common stock:

 
  Range of
Implied Present
Value per Share
(perpetuity
growth method)
  Range of
Implied Present
Value per Share
(long-term earnings
multiples method)

Janus Management Forecast

  $12.71 - $19.22   $16.55 - $19.38

Henderson:

        Loeb Spencer House conducted a discounted cash flow analysis for Henderson based on the Henderson Management Forecast by:

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        These analyses resulted in the following reference range of implied equity value per share of Henderson ordinary shares:

 
  Range of
Implied Present
Value per Share
(perpetuity
growth method)
  Range of
Implied Present
Value per Share
(long-term earnings
multiples method)

Henderson Management Forecast

  £2.17 - £3.25   £2.77 - £3.25

        Based on comparing the upper and lower limits of these reference ranges of implied equity value per share of Janus common stock and Henderson ordinary shares (converted to U.S. dollars at the FactSet Research Systems exchange rate on September 30, 2016), Loeb Spencer House derived a range of implied exchange ratios of Henderson ordinary shares to shares of Janus common stock of 4.51 to 4.55 using the perpetuity growth rate methodology and 4.59 to 4.60 using the long-term earnings multiple methodology, as compared to the exchange ratio of 4.7190 Henderson ordinary shares to be received for each share of Janus common stock as provided for in the merger agreement, which was above both such ranges.

Earnings Contribution Analysis

        Loeb Spencer House analyzed the implied earnings contribution of Janus and Henderson to the combined company using the Janus Management Forecast and Henderson Management Forecast, respectively, of net income of Janus and Henderson for years 2017 through 2020 and the consensus median estimate of net income for Janus and Henderson for the years 2017 through 2018:

 
  Implied Earnings Contribution
 
  Janus   Henderson

Management Forecasts (2017 - 2020)

  42.1% - 44.0%   56.0% - 57.9%

Consensus Median Estimates (2017 - 2018)

  41.7% - 46.9%   53.1% - 58.3%

        From the implied earnings contribution, Loeb Spencer House derived a range of implied exchange ratios of Henderson ordinary shares to shares of Janus common stock of 4.48 to 4.85 based on the Janus Management Forecast and the Henderson Management Forecast and 4.42 to 5.45 based on the consensus median estimates, as compared to the exchange ratio of 4.7190 Henderson ordinary shares to be received for each share of Janus common stock as provided for in the merger agreement, which was within each of such ranges.

Other Factors

        Loeb Spencer House also observed certain additional factors that were not considered part of Loeb Spencer House's financial analyses with respect to its opinion but were provided to the board of directors of Janus for informational purposes, including the following:

Illustrative Future Earnings Accretion for Janus Shareholders

        Loeb Spencer House performed an illustrative analysis of the potential future earnings accretion for Janus shareholders, using the Janus Management Forecast, the Henderson Management Forecast and synergy estimates provided by Janus management. For each of the years 2017 through 2020 ending December 31, Loeb Spencer House compared the projected net income of Janus on a stand-alone basis to the projected net income of the pro forma combined company, including estimated synergies, taking into account Janus shareholders' pro forma ownership of the combined company based upon the exchange ratio. This analysis indicated the combination would be accretive to the holders of shares of

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Janus common stock on a net income basis in each of the years 2017 through 2020 ending December 31.

Illustrative Hypothetical Net Present Value Accretion

        Loeb Spencer House performed an illustrative analysis of the hypothetical net present value accretion for Janus shareholders, using the Janus Management Forecast, the Henderson Management Forecast and synergy and transaction cost estimates provided by Janus management. For this analysis, Loeb Spencer House compared the stand-alone discounted cash flow valuation for Janus utilizing the perpetuity growth terminal value method with the combined discounted cash flow valuation for each of Janus and Henderson, plus the discounted present value of synergies and minus the discounted present value of transaction costs, taking into account Janus's shareholders pro forma ownership of the combined company based upon the exchange ratio. On a per share basis, the stand-alone discounted value per share ranging from $12.71 to $19.22 compared to a range of $14.49 to $22.08 reflecting net cost synergies and a range of $15.55-$23.79 reflecting total net synergies.

        The implied present value of future prices per share of Janus common stock was reviewed for illustrative purposes only. The illustrative future prices per share of Janus common stock should not be viewed as an accurate representation of what actual prices per share of Janus common stock will be. Actual prices per share of Janus common stock for any period may be greater or less than the illustrative future prices per share of Janus common stock reviewed by Loeb Spencer House, and the differences may be material. Future share prices are inherently uncertain, being based upon numerous factors or events that are not possible to predict.

Miscellaneous

        The preparation of a fairness opinion is a complex process and is not necessarily susceptible to partial analysis or summary description. Selecting portions of the analyses or of the summary set forth above, without considering the analyses as a whole, could create an incomplete view of the processes underlying Loeb Spencer House's opinion. In arriving at its fairness determination, Loeb Spencer House considered the results of all of its analyses and did not attribute any particular weight to any factor or analysis considered by it. Rather, Loeb Spencer House made its determination as to fairness on the basis of its experience and professional judgment after considering the results of all of its analyses. No company or transaction used in the above analyses as a comparison is directly comparable to Janus or Henderson or the contemplated combination.

        Loeb Spencer House prepared these analyses solely for purposes of Loeb Spencer House's providing its opinion to the Janus board as to the fairness from a financial point of view to the holders of shares of Janus common stock (other than Janus or any wholly-owned subsidiary of Janus or Henderson and its affiliates) of the exchange ratio set forth in the merger agreement. These analyses do not purport to be appraisals nor do they necessarily reflect the prices at which businesses or securities actually may be sold or traded. Analyses based upon forecasts of future results are not necessarily indicative of actual future results, which may be significantly more or less favorable than suggested by these analyses. Because these analyses are inherently subject to uncertainty, being based upon numerous factors or events beyond the control of the parties or their respective advisors, none of Janus, Henderson, Loeb Spencer House or any other person assumes responsibility if future results are materially different from those forecast.

        The exchange ratio was determined through arm's-length negotiations between Janus and Henderson and was approved by the Janus board. Loeb Spencer House provided advice to Janus during these negotiations. Loeb Spencer House did not, however, recommend any specific exchange ratio to Janus or the Janus board or that any specific exchange ratio constituted the only appropriate

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exchange ratio for the combination. The decision to enter into the merger agreement was solely that of Janus's board of directors.

        As described above, Loeb Spencer House's opinion to the Janus board was one of many factors taken into consideration by the Janus board in making its determination to approve the merger agreement and should not be viewed as determinative of the views of Janus's board of directors or management with respect to the merger or the exchange ratio. The foregoing summary does not purport to be a complete description of the analyses performed by Loeb Spencer House in connection with the fairness opinion and is qualified in its entirety by reference to the written opinion of Loeb Spencer House attached as Annex C.

        Loeb Spencer House is acting as financial advisor to the Janus board in connection with the merger and will receive a fee for such services based on a percentage of the value of the consideration to be received by the holders of Janus common stock which is expected to be up to approximately $9 million based on the trading price of Henderson ordinary shares at the close of business on September 30, 2016, the last trading day prior the announcement of the transaction, and a fee of $750,000, which was payable upon its rendering of its opinion. In addition, Janus has agreed to reimburse Loeb Spencer House's expenses and indemnify Loeb Spencer House and its affiliates and their respective directors, officers, members, employees, agents and controlling persons against certain liabilities arising out of its engagement, including liabilities under federal securities laws.

        During the two year period prior to October 1, 2016, Loeb Spencer House did not provide financial advisory services to Janus or Henderson. Loeb Spencer House may provide financial or other services to Janus or Henderson in