# EDGAR Filing Document

**Accession Number:** 0001345471
**File Stem:** 0000930413-26-000860
**Filing Date:** 2026-3
**Character Count:** 66667
**Document Hash:** 3d35a81a8fe7c6e31d5e88e95d87b09a
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000930413-26-000860.hdr.sgml**: 20260324

**ACCESSION NUMBER**: 0000930413-26-000860

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D/A

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20260324

**DATE AS OF CHANGE**: 20260324

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** JANUS HENDERSON GROUP PLC
- **CENTRAL INDEX KEY:** 0001274173
- **STANDARD INDUSTRIAL CLASSIFICATION:** INVESTMENT ADVICE [6282]
- **ORGANIZATION NAME:** 02 Finance
- **EIN:** 000000000
- **STATE OF INCORPORATION:** Y9
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-90000
- **FILM NUMBER:** 26788215

**BUSINESS ADDRESS:**
- **STREET 1:** 201 BISHOPSGATE
- **CITY:** LONDON
- **STATE:** X0
- **ZIP:** EC2M 3AE
- **BUSINESS PHONE:** 442078181818

**MAIL ADDRESS:**
- **STREET 1:** 201 BISHOPSGATE
- **CITY:** LONDON
- **STATE:** X0
- **ZIP:** EC2M 3AE

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** HENDERSON GROUP PLC
- **DATE OF NAME CHANGE:** 20050511

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** HHG PLC
- **DATE OF NAME CHANGE:** 20031223
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** TRIAN FUND MANAGEMENT, L.P.
- **CENTRAL INDEX KEY:** 0001345471

**ORGANIZATION NAME:**
- **EIN:** 203454182
- **STATE OF INCORPORATION:** DE

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A

**BUSINESS ADDRESS:**
- **STREET 1:** 280 PARK AVENUE
- **STREET 2:** 41ST FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10017
- **BUSINESS PHONE:** 212-451-3000

**MAIL ADDRESS:**
- **STREET 1:** 280 PARK AVENUE
- **STREET 2:** 41ST FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10017

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Trian Fund Management, L.P.
- **DATE OF NAME CHANGE:** 20051128

## Ex-11

**Exhibit 11**

<u>EXECUTION VERSION</u>

March 24, 2026

Jupiter Company Limited

c/o Trian Fund Management, L.P.

280 Park Avenue

41<sup>st</sup> Floor

New York, NY 10017

Re: Amended and Restated Equity Financing Commitment

Ladies and Gentlemen:

Reference is made to the Agreement and Plan of Merger, dated as of December 21, 2025, as amended by Amendment No. 1 thereto dated as of the date hereof (as amended, supplemented or otherwise modified from time to time in accordance with its terms, the "**Merger Agreement**"), by and among Jupiter Company Limited, a private limited company organized under the laws of Jersey ("**Parent**"), Jupiter Merger Sub Limited, a private limited company organized under the laws of Jersey ("**Merger Sub**" and, together with Parent, the "**Parent Entities**"), and Janus Henderson Group plc, a public limited company organized under the laws of Jersey (the "**Company**"). Pursuant to the Merger Agreement, on the terms and subject to the conditions set forth therein, among other things, Parent will acquire the Company by causing the merger of Merger Sub with and into the Company, with the Company surviving as a wholly owned subsidiary of Parent (the "**Merger**") or, following a Switch, via a Scheme of Arrangement. Reference is also made to (a) that certain Equity Commitment Letter delivered to Parent by the GC Investor as of the date hereof, (b) the other Equity Commitment Letter delivered to Parent by the QIA Investor on December 21, 2025 (collectively, the "**Other Equity Commitment Letters**," and together with this letter agreement, the "**Equity Commitment Letters**"), (c) the Guarantee (as defined below) and (d) the other Limited Guarantees, dated as of December 21, 2025, delivered to the Company by the GC Investor and the QIA Investor (collectively, the "**Other Guarantees**," and together with the Guarantee (as defined below), the "**Guarantees**"). Each capitalized term used but not otherwise defined herein shall have the meaning ascribed to such term in the Merger Agreement.

Each Person listed on <u>Schedule A</u> hereto is referred to herein as an "**Equity Investor**" and, such Persons collectively, the "**Equity Investors**," and each of the "Equity Investors" under the Other Equity Commitment Letters are referred to herein as an "**Other Equity Investor**" and collectively as the "**Other Equity Investors**". This letter agreement is being delivered by the Equity Investors to Parent in connection with the execution and delivery of the Merger Agreement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. <u>Commitment</u>. Subject to the conditions set forth herein, each Equity Investor hereby irrevocably agrees to purchase immediately prior to the Closing, directly or indirectly, equity interests of Parent (collectively, the "**Subject Equity Securities**") for an aggregate purchase price, in the form of cash in immediately available U.S. funds to Parent, in an amount equal to such Equity Investor's pro rata share, as set forth opposite such Equity Investor's name on <u>Schedule A</u> hereto (such proportion for such Equity Investor, as may be adjusted pursuant to the terms hereof, being its "**Pro Rata Share**"), of six hundred sixteen million six hundred thousand dollars ($616,600,000), as may be adjusted in accordance with this letter agreement (the "**Equity Financing Commitment**"), such that the aggregate purchase price for all such equity interests purchased by all such Equity Investors shall equal the Equity Financing Commitment. The Equity Financing Commitment shall be used by the Parent Entities solely for the purpose of funding at the Closing, along with the other proceeds of the Financing (when funded), the Financing Amounts pursuant to and in accordance with the terms and conditions of the Merger Agreement, and not for any other purpose; <u>provided</u>, that each Equity Investor (together with its permitted assigns, as applicable) shall not under any circumstances be obligated under this letter agreement to fund an amount in excess of its Pro

Rata Share of the Equity Financing Commitment. The Equity Investors' obligations to fund their Pro Rata Shares of the Equity Financing Commitment are several and not joint or joint and several such that each Equity Investor (together with its permitted assigns, as applicable) is only obligated to fund its Pro Rata Share of the Equity Financing Commitment, subject to the terms and conditions herein. The obligation of each Equity Investor (together with its permitted assigns, as applicable) to fund its Pro Rata Share of the Equity Financing Commitment is subject solely to (a) the satisfaction or waiver of the conditions precedent to the Parent Entities' obligations to effect the Closing set forth in Sections 8.1 and 8.2 of the Merger Agreement (other than those conditions that by their nature are to be satisfied at the Closing, but subject to such conditions being able to be satisfied (or waived)); (b) the prior or substantially concurrent (i) consummation of the Exchange (as defined in the Voting and Rollover Agreement), and (ii) funding of the proceeds of the Equity Financing Commitments (as defined in each Other Equity Commitment Letter) under the Other Equity Commitment Letters, the Preferred Equity Financing pursuant to the Preferred Equity Commitment Letter and the Debt Financing pursuant to the Debt Commitment Letter (or any Alternative Financing), or such other Equity Financing Commitments, Preferred Equity Financing or Debt Financing (or any Alternative Financing) will be funded and the Exchange will be consummated if the other Financing (or any Alternative Financing) is funded and, in the case of the other Financing (or any Alternative Financing), if the Exchange and contributions contemplated by <u>Section 6.1</u>, <u>Section 6.2</u> and <u>Section 6.3</u> of the Voting and Rollover Agreement are consummated; and (c) the substantially concurrent consummation of the Closing on the terms and subject to the conditions of the Merger Agreement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. <u>Adjustment to Equity Financing Commitment</u>. The amount to be funded under this letter agreement may be reduced dollar for dollar (any such reduction to be allocated between the Equity Investors on a *pro rata* basis) solely to the extent that the Parent Entities do not require the full amount of the Equity Financing Commitment in connection with the payment of the Financing Amounts. It is understood and agreed that any reduction pursuant to this paragraph shall only occur to the extent that, after giving effect to any such reduction, the Parent Entities fully and timely consummate the transactions contemplated by the Merger Agreement (including, for the avoidance of doubt, payment of the Financing Amounts in full at the Closing) (the "**<u>Transactions</u>**") in accordance with the terms of the Merger Agreement. The aggregate amount to be funded under this letter agreement and the Other Equity Commitment Letters may also be reduced dollar for dollar (and such reduction to be allocated among the Equity Financing Commitment and the other equity financing commitments under the Other Equity Commitment Letters on a *pro rata* basis) by an amount equal to the Merger Consideration that would have been payable in respect of the shares of Company Common Stock in excess of the Rollover Minimum (as defined in the Voting and Rollover Agreement) that are owned by Parent or Merger Sub or any of their respective Subsidiaries immediately prior to the Effective Time (after giving effect to the transactions contemplated by <u>Section 6.1</u>, <u>Section 6.2</u> and <u>Section 6.3</u> of the Voting and Rollover Agreement) and for which the Equity Investors agree irrevocably in writing (with a copy to the Company) that such shares of Company Common Stock shall be Stockholder Rollover Shares pursuant to the Merger Agreement and "Rollover Shares" pursuant to the Voting and Rollover Agreement, it being understood that any such reduction pursuant to this paragraph shall only occur to the extent that such Stockholder Rollover Shares are treated as Stockholder Rollover Shares under the Merger Agreement at the Effective Time. For clarity, there shall be no such reduction to the Equity Financing Commitment or the other equity financing commitments under the Other Equity Commitment Letters in respect of the shares of Company Common Stock constituting the Rollover Minimum under the Voting and Rollover Agreement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3. <u>Termination</u>. This letter agreement and each Equity Investor's obligation to fund its Pro Rata Share of the Equity Financing Commitment will terminate automatically and immediately upon the earliest to occur of: (a) the valid termination of the Merger Agreement in accordance with its terms; (b) the commencement by the Company or any of its controlled Affiliates or any of their respective representatives acting on their behalf at their direction or with their express written consent, of any lawsuit against the

Equity Investors, the Parent Entities or any Parent Related Party (as defined below) in respect of this letter agreement, the limited guarantee of the Equity Investors and Trian Partners AM Holdco II, Ltd., a Cayman Islands exempted limited company (the "**Rollover Shareholder**"), dated December 21, 2025, as amended and restated as of the date hereof (the "**Guarantee**"), the Voting and Rollover Agreement or the Merger Agreement (including in respect of any oral representations made or alleged to be made in connection therewith) that asserts (i) the Equity Investors' liability under or in respect of this letter agreement is not limited to the Equity Financing Commitment or that any Equity Investor's liability under this letter agreement is not limited to its Pro Rata Share of the Equity Financing Commitment or (ii) any theory of liability against the Equity Investors, the Parent Entities or any Parent Related Party (as defined below), in each case other than any claims or other Proceedings (A) against the Equity Investors, the Rollover Shareholder or any other Guarantors (as defined in the Merger Agreement) (or their respective permitted assignees and successors) in accordance with, and solely to the extent permitted under, the terms of the Guarantee or any Other Guarantees, as applicable, (B) against the Parent Entities (or their respective permitted assignees and successors) for remedies (whether for equitable relief or otherwise) available to the Company under the Merger Agreement, in each case in accordance with, and solely to the extent permitted under, the Merger Agreement, (C) against the Equity Investors or Other Equity Investors (or their permitted assignees and successors) for specific performance of, or other equitable relief that enforces, the Equity Investors' obligations to fund the Equity Financing Commitment or such Other Equity Investors' obligations to fund their respective commitments under the Other Equity Commitment Letters, or other equitable relief to enforce the Company's other express-third party beneficiary rights under this letter agreement or the Other Equity Commitment Letters, in each case in accordance with, and solely to the extent permitted under, the terms hereof or thereof and the terms of the Merger Agreement, (D) against the parties (or their permitted assignees and successors) to the Voting and Rollover Agreement in accordance with, and solely to the extent permitted under, the terms of the Voting and Rollover Agreement and/or (E) against the parties (or their permitted assignees and successors) to the Confidentiality Agreements in accordance with, and solely to the extent permitted under, the terms thereunder (the Proceedings contemplated by the foregoing <u>clauses (A)</u>, <u>(B)</u>, <u>(C)</u>, <u>(D)</u> and <u>(E)</u>, the "**Non-Prohibited Claims**"); (c) any final, non-appealable judgement of a Chosen Court against the Equity Investors and the Rollover Shareholder that includes an award of the Parent Termination Fee; (d) the valid termination of the Other Equity Commitment Letters in accordance with their terms due to a lawsuit against the Equity Investors, the Parent Entities or any Parent Related Party for a claim (other than a Non-Prohibited Claim) being asserted; and (e) the consummation of the Closing and payment in full at the Closing of the Equity Financing Commitment. Upon the valid termination of this letter agreement pursuant to the terms hereof, the Equity Investors shall not have any further obligations or liabilities hereunder. This <u>Section 3</u> (*Termination*), <u>Section 4</u> (*Assignment; Amendments and Waivers; Entire Agreement*), <u>Section 5</u> (*Parties in Interest; Limited Recourse; Enforcement*), <u>Section 6</u> (*Confidentiality*), <u>Section 7</u> (*Governing Law; Jurisdiction; Waiver of Jury Trial*), <u>Section 8</u> (*Headings; Severability; Construction*) and <u>Section 9</u> (*Counterparts*) of this letter agreement shall survive and remain in full force and effect, notwithstanding any termination of this letter agreement. For the avoidance of doubt, upon the valid termination of this letter agreement pursuant to the terms hereof, all obligations of the Equity Investors to fund the Equity Financing Commitment shall terminate and no surviving provision shall be deemed to require the Equity Investors to fund any portion of the Equity Financing Commitment.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;4. <u>Assignment; Amendments and Waivers; Entire Agreement</u>.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) The rights and obligations under this letter agreement may not be assigned or delegated (whether by operation of law, merger, consolidation or otherwise) by any party hereto without the prior written consent of the other parties and the Company (and the Company shall be an express and intended third-party beneficiary of this <u>Section 4(a)</u>). Notwithstanding the foregoing, (i) Parent may assign, delegate or otherwise transfer all or a portion of their rights or obligations under this letter agreement to any assignee

of Parent's obligations under the Merger Agreement pursuant to an assignment in accordance with Section 10.3 of the Merger Agreement, and (ii) each Equity Investor may assign, delegate or otherwise transfer all or a portion of its obligation to fund the Equity Financing Commitment to one or more of its Affiliated investment vehicles or any Person that is, directly or indirectly, wholly owned or otherwise controlled by or Affiliated with such Equity Investor or such Affiliated investment vehicles; <u>provided</u> that, (x) in each case of the foregoing <u>clauses (i)</u> and <u>(ii)</u>, no such assignment, delegation or transfer shall relieve the Equity Investors of their obligations hereunder, and (y) in each case of the foregoing <u>clauses (i)</u> and <u>(ii)</u>, no such assignment, delegation and/or transfer will be permitted if it would reasonably be expected to have the effect of preventing, impairing or delaying the Transactions or the funding of the Equity Financing Commitment at the time set forth in <u>Section 1</u>. Upon any such assignment, delegation or transfer by an Equity Investor of its obligations hereunder pursuant to the second sentence of this <u>Section 4(a)</u>, such assignee, delegate or transferee shall be deemed to have given the representations and warranties set forth in <u>Section 10</u> as of the time of such assignment, delegation or transfer. Any assignment, delegation or transfer in breach of <u>Section 10</u> (in respect of the representations and warranties deemed to be made as of the time of such assignment, delegation or transfer) or in violation of this <u>Section 4(a)</u> shall be null and void and of no force and effect.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) This letter agreement may not be amended, and no provision hereof waived or modified, except by an instrument duly executed by each of the parties hereto and the Company (and the Company shall be an express and intended third-party beneficiary of this <u>Section 4(b)</u>). This letter agreement may not be terminated other than in accordance with Section 3 hereof. The failure of any party or third-party beneficiary to assert any of its rights under this letter agreement or otherwise shall not constitute a waiver of those rights.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) This letter agreement, the Other Equity Commitment Letters, the Guarantees, the Voting and Rollover Agreement, the Confidentiality Agreements and the Merger Agreement and the documents referenced therein contain the entire understanding among the parties hereto and the Company with respect to the transactions contemplated hereby and supersede and replace all prior and contemporaneous agreements and understandings, oral or written, with regard to such transactions between the Equity Investor or any of its Affiliates, on the one hand, and the Parent Entities or any of their Affiliates, on the other hand, with respect to the subject matter hereof and thereof. All Exhibits and Schedules hereto and any documents and instruments delivered pursuant to any provision hereof are expressly made a part of this Agreement as fully as though completely set forth herein.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5. <u>Parties in Interest; Limited Recourse; Enforcement</u>.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) Except to the extent expressly set forth in <u>Section 4(a)</u>, <u>Section 4(b)</u> and <u>Section 5(c)</u>, this letter agreement shall be binding upon and inure solely to the benefit of each party hereto and their respective successors and permitted assigns, and nothing in this letter agreement, express or implied, is intended to or shall confer upon any other Person any right, benefit or remedy of any nature whatsoever under or by reason of this letter agreement; <u>provided</u>, <u>however</u> that the Parent Related Parties and the Company are express and intended third party beneficiaries of <u>Section 5(c)</u> hereto.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) Notwithstanding anything that may be expressed or implied in this letter agreement, the Guarantee, the Merger Agreement or any document or instrument delivered in connection herewith or therewith, the Parent Entities, by their acceptance of the benefits of the Equity Financing Commitment provided herein, covenant, agree and acknowledge that no Person other than the Equity Investors (and their successors and permitted assigns) shall have any obligations hereunder and that, notwithstanding that each Equity Investor or any of its permitted assigns may be a partnership or limited liability company, no Person, including the Parent Entities, has any rights of recovery pursuant to this letter agreement against, and no

recourse hereunder or in respect of any oral representations made or alleged to have been made in connection herewith shall be had against, any of the Parent Entities', the Equity Investors' or the Rollover Shareholder's or any of their or their respective Affiliates' respective former, current or future directors, officers, employees, direct or indirect holders of any equity, stockholders, controlling persons, attorneys, members, managers, general or limited partners, assignees (other than a permitted assignee hereunder), agents or representatives of any of the foregoing (other than, in each applicable case, the Parent Entities, the Equity Investors, the Other Equity Investors, the Rollover Shareholder, the Guarantors (as defined in the Merger Agreement), Midco (as defined in the Voting and Rollover Agreement), Topco (as defined in the Voting and Rollover Agreement) and their respective successors and permitted assigns, a "**Parent Related Party**" and together, the "**Parent Related Parties**"), whether by or through attempted piercing of the corporate (or limited liability company or limited partnership) veil, by or through a claim (whether at law or equity or in tort, contract or otherwise) by or on behalf of the Equity Investors against any Parent Related Party (or vice versa), by the enforcement of any assessment or by any legal or equitable proceeding, or by virtue of any Applicable Law, or otherwise, it being agreed and acknowledged that no personal liability whatsoever shall attach to, be imposed on or otherwise be incurred by any Parent Related Party for any obligations of any Equity Investor or any of its successors or permitted assigns under this letter agreement or the Merger Agreement or under any documents or instruments delivered in connection herewith or therewith in respect of any transaction contemplated hereby or in respect of any oral representations made or alleged to have been made in connection herewith or for any claim (whether at law or equity or in tort, contract or otherwise) based on, in respect of, or by reason of such obligations or their creation; <u>provided</u>, <u>however</u>, that notwithstanding anything to the contrary provided herein or any document or instrument delivered in connection herewith, nothing herein (including this <u>Section 5</u>) shall limit the Non-Prohibited Claims or the third-party beneficiary rights made expressly available to the Company hereunder.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) This letter agreement may only be enforced by the Parent Entities, and none of the Parent Entities' creditors nor any other Person that is not a party to this letter agreement shall have any right to enforce this letter agreement or to cause the Parent Entities to enforce this letter agreement; <u>provided</u>*,* <u>however</u>, that the Company is hereby made an express and intended third party beneficiary of the rights granted to the Parent Entities under this letter agreement only for the purpose of (i) specifically enforcing the obligations of the Equity Investors (or their respective successors or permitted assigns) to, or the obligations of the Parent Entities to cause the Equity Investors (or their respective successors or permitted assigns) to, comply with the terms of this letter agreement, including to satisfy each Equity Investor's obligation to fund its Pro Rata Share of the Equity Financing Commitment hereunder (subject to the limitations set forth in this letter agreement, including <u>Section 1</u> of this letter agreement), in each case subject to the conditions set forth in Section 10.4(d) of the Merger Agreement (solely to the extent that the Parent Entities are permitted to enforce the Equity Financing Commitment pursuant to <u>Section 1</u> of this letter agreement), and, subject to clause (ii) of this proviso, for no other purpose (including, without limitation, any claim for monetary damages hereunder or under the Merger Agreement) and (ii) <u>Sections 4(a)</u> and <u>4(b) provided further</u>, however, that the Parent Entities and the Company may not bring a claim or Proceeding against the Equity Investors hereunder or enforce or seek to enforce the provisions hereof unless the Parent Entities or the Company are seeking the same relief from the Other Equity Investors to the extent that the Other Equity Investors have not satisfied their respective obligations under the Other Equity Commitment Letters. Each Equity Investor acknowledges and agrees that (I) the Parent Entities are delivering a copy of this letter agreement to the Company and that the Company is relying on the express third-party beneficiary rights, representations, warranties, obligations and commitments of such Equity Investor hereunder in connection with the Company's decision to enter into the Merger Agreement and consummate the Transactions, and (II) the enforcement rights under this <u>Section 5(c)</u> (subject to the requirements and limitations herein and in the Merger Agreement) are an integral part of the Transactions and without those rights, the Company would not have entered into the Merger Agreement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) Concurrently with the execution and delivery of this letter agreement, the Equity Investors and the Rollover Shareholder are executing and delivering to the Company the Guarantee relating to the Obligations (as defined under the Guarantee).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6. <u>Confidentiality</u>. This letter agreement shall be treated as confidential and is being provided to Parent solely in connection with the Merger Agreement. This letter agreement may not be used, circulated, quoted or otherwise referred to in any document, except with the written consent of the Equity Investors; <u>provided</u> that no such written consent shall be required for disclosures by Parent to the Company (or their respective representatives) so long as the Company agrees to (and to cause their respective representatives to) keep such information confidential on terms substantially identical to the terms contained in this <u>Section 6</u>; <u>provided</u>, <u>further</u>, that any party hereto may disclose the existence of this letter agreement to the extent required by any Applicable Law, the applicable rules of any national securities exchange, in connection with any securities regulatory agency filings relating to the transactions contemplated by the Merger Agreement (including the Proxy Statement or Schedule 13e-3 to be filed by the Company), or in connection with the enforcement of any such party's rights hereunder or under the Other Equity Commitment Letters, the Guarantees, the Voting and Rollover Agreement, the Confidentiality Agreements or the Merger Agreement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7. <u>Governing Law; Jurisdiction; Waiver of Jury Trial</u>. This letter agreement shall be construed, performed and enforced in accordance with, and governed by, the laws of the State of Delaware. Each of the parties hereto irrevocably agrees that any legal action or proceeding with respect to this letter agreement and the rights and obligations arising hereunder, or for recognition and enforcement of any judgment in respect of this letter agreement and the rights and obligations arising hereunder brought by the other party(ies) hereto or its successors or assigns shall be brought and determined exclusively in the Delaware Court of Chancery, or in the event (but only in the event) that such court does not have subject matter jurisdiction over such action or proceeding, in the U.S. District Court for the District of Delaware, or, in each case, any applicable appellate court therefrom (the "<u>Chosen Courts</u>"). In addition, each of the parties hereto (i) expressly submits to the personal jurisdiction and venue of the Chosen Courts, in the event any dispute between the parties hereto (whether in contract, tort or otherwise) arises out of this letter agreement, (ii) expressly waives any claim of lack of personal jurisdiction or improper venue and any claims that such courts are an inconvenient forum with respect to such a claim, and (iii) agrees that it shall not bring any claim, action or proceeding against any other parties hereto relating to this letter agreement in any court other than the Chosen Courts. Each of the parties hereto hereby agrees that service of process will be validly effected by sending notice in the manner set forth in Section 10.7 of the Merger Agreement (if to the Equity Investors, to the applicable addresses set forth on Schedule A, and if to Parent, to the applicable addresses set forth in Section 10.7 of the Merger Agreement). EACH PARTY HEREBY IRREVOCABLY AND UNCONDITIONALLY WAIVES ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY LITIGATION DIRECTLY OR INDIRECTLY ARISING OUT OF OR RELATING TO THIS LETTER AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY. EACH PARTY CERTIFIES AND ACKNOWLEDGES THAT (I) NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE EITHER OF SUCH WAIVERS, (II) IT UNDERSTANDS AND HAS CONSIDERED THE IMPLICATIONS OF SUCH WAIVERS, (III) IT MAKES SUCH WAIVERS VOLUNTARILY, AND (IV) IT HAS BEEN INDUCED TO ENTER INTO THIS AGREEMENT BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS IN THIS <u>SECTION 7</u>.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8. <u>Headings; Severability; Construction</u>. The section and paragraph headings in this letter agreement are for reference purposes only and shall not affect the meaning or interpretation of this letter agreement. In the event that any part of this letter agreement is declared by any court or other judicial or administrative body to be null, void or unenforceable, said provision shall survive to the extent it is not so

declared, and all of the other provisions of this letter agreement shall remain in full force and effect. The parties have participated jointly in the negotiation and drafting of this letter agreement. If any ambiguity or question of intent arises, this letter agreement will be construed as if drafted jointly by the parties and no presumption or burden of proof will arise favoring or disfavoring any party because of the authorship of any provision of this letter agreement. Reference to any Person shall include such Person's successors and permitted assigns.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9. <u>Counterparts</u>. This letter agreement may be executed in counterparts, (including by facsimile or other electronic transmission) each of which shall be deemed an original, but all of which shall constitute the same instrument.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10. <u>Representations and Warranties</u>. Each Equity Investor hereby represents and warrants to Parent that: (a) it is duly organized or incorporated, validly existing and in good standing (to the extent such concept exists) under the Applicable Laws of its jurisdiction of organization or incorporation and has all power and authority to execute, deliver and perform this letter agreement; (b) the execution, delivery and performance of this letter agreement by it has been duly and validly authorized and approved by all necessary organizational action by it and no other proceedings or actions on the part of it are necessary therefor; (c) this letter agreement has been duly and validly executed and delivered by it and constitutes a valid and legally binding obligation of it, enforceable against it in accordance with the terms of this letter agreement, subject to (i) the effect of bankruptcy, fraudulent conveyance, reorganization, moratorium and other similar laws relating to or affecting the enforcement of creditors' rights generally, and (ii) general equitable principles (whether considered in a proceeding in equity or at law); (d) its Pro Rata Share of the Equity Financing Commitment is less than or equal to the maximum amount that it is permitted to invest in any one portfolio investment pursuant to the terms of its constituent documents or otherwise; (e) as of the date hereof, it has, and until the valid termination of this letter agreement in accordance with Section 3 hereof, it will have, uncalled capital commitments (and an enforcement right to cause such capital to be contributed) or other available funds on hand in an amount at least equal to its Pro Rata Share of the Equity Financing Commitment plus the aggregate amount of all other commitments and obligations it has outstanding; (f) all consents, approvals, authorizations, permits of, filings with and notification to, any Governmental Entity necessary for the due execution, delivery and performance of this letter agreement by it have been obtained or made and all conditions thereof have been duly complied with, and no other action by, and no notice to or filing with, any Governmental Entity is required in connection with the execution, delivery or performance by it of this letter agreement; and (g) the execution, delivery and performance by such Equity Investor of this letter agreement do not and will not (i) violate its organizational documents, (ii) violate any Applicable Law or judgment applicable to it or (iii) result in any violation of, or default (with or without notice or lapse of time or both) under, or give rise to a termination, cancellation or acceleration of any obligation or to the loss of any benefit under, any contract to which it is a party, except, with respect to each of the foregoing clauses (ii) and (iii), for any such conflicts, violations, breaches, defaults or other occurrences which would not reasonably be expected to, individually or in the aggregate, prevent, materially delay or materially impair its ability to enter into or perform its obligations under this letter agreement.

[Signature Pages Follow]

---

| | |
|:---|:---|
| Very Truly Yours, | Very Truly Yours, |
| **JUPITER CORE HOLDINGS, L.P.** | **JUPITER CORE HOLDINGS, L.P.** |
| By: | JUPITER PRINCIPAL HOLDINGS GP, L.P., its general partner |
| By: | JUPITER VOTING COMPANY, LLC, its general partner |
| By: | /s/ Nelson Peltz |
| Name: | Nelson Peltz |
| Title: | Manager |
| **JUPITER AM INVESTORS, L.P.** | **JUPITER AM INVESTORS, L.P.** |
| By: | JUPITER AM INVESTORS GP, L.P., its general partner |
| By: | JUPITER VOTING COMPANY, LLC, its general partner |
| By: | /s/ Nelson Peltz |
| Name: | Nelson Peltz |
| Title: | Manager |
| **TRIAN PARTNERS AM FUND, L.P.** | **TRIAN PARTNERS AM FUND, L.P.** |
| By: | TRIAN PARTNERS AM FUND GP, L.P. |
| By: | TRIAN PARTNERS AM FUND GENERAL PARTNER, LLC |
| By: | /s/ Nelson Peltz |
| Name: | Nelson Peltz |
| Title: | Member |
| **TRIAN PARTNERS AM PARALLEL FUND, L.P.** | **TRIAN PARTNERS AM PARALLEL FUND, L.P.** |
| By: | Trian Partners AM Parallel Fund GP, L.P. |
| By: | Trian Partners AM Parallel Fund General Partner, LLC |
| By: | /s/ Nelson Peltz |
| Name: | Nelson Peltz |
| Title: | Member |

---

[Signature Page to Amended and Restated Equity Commitment Letter]

---

| | |
|:---|:---|
| Acknowledged and Agreed: | Acknowledged and Agreed: |
| **JUPITER COMPANY LIMITED** | **JUPITER COMPANY LIMITED** |
| By: | /s/ Nelson Peltz |
| Name: | Nelson Peltz |
| Title: | Authorized Signatory |

---

[Signature Page to Amended and Restated Equity Commitment Letter]

**<u>Schedule A</u>**

Pro Rata Share

---

| | |
|:---|:---|
| &nbsp;&nbsp;**Equity Investor** | |
| &nbsp;&nbsp;Jupiter Core Holdings, L.P. | &nbsp;&nbsp;Jupiter Core Holdings, L.P. &nbsp;&nbsp;[\*\*\*]<sup>1</sup>% |
| &nbsp;&nbsp;*Notices:* |  |
| &nbsp;&nbsp;c/o Trian Fund Management, L.P. | &nbsp;&nbsp;c/o Trian Fund Management, L.P. |
| &nbsp;&nbsp;280 Park Avenue |  |
| &nbsp;&nbsp;41st Floor |  |
| &nbsp;&nbsp;New York, NY 10017 | &nbsp;&nbsp;New York, NY 10017 |
| &nbsp;&nbsp;E-Mail: | bschorr@trianpartners.com |
|  | dmarx@trianpartners.com |
| &nbsp;&nbsp;Attention: | Brian L. Schorr |
|  | Daniel R. Marx |
| &nbsp;&nbsp;with a copy (which shall not constitute notice) to: | &nbsp;&nbsp;with a copy (which shall not constitute notice) to: |
| &nbsp;&nbsp;Debevoise & Plimpton LLP | &nbsp;&nbsp;Debevoise & Plimpton LLP |
| &nbsp;&nbsp;66 Hudson Boulevard | &nbsp;&nbsp;66 Hudson Boulevard |
| &nbsp;&nbsp;New York, NY 10001 | &nbsp;&nbsp;New York, NY 10001 |
| &nbsp;&nbsp;E-Mail: | wdregner@debevoise.com |
|  | efhuang@debevoise.com |
| &nbsp;&nbsp;Attention: | William D. Regner |
|  | Emily F. Huang |
| &nbsp;&nbsp;Jupiter AM Investors, L.P. | &nbsp;&nbsp;Jupiter AM Investors, L.P. &nbsp;&nbsp;[\*\*\*]<sup>2</sup>% |
| &nbsp;&nbsp;*Notices:* |  |
| &nbsp;&nbsp;c/o Trian Fund Management, L.P. | &nbsp;&nbsp;c/o Trian Fund Management, L.P. |
| &nbsp;&nbsp;280 Park Avenue |  |
| &nbsp;&nbsp;41st Floor |  |
| &nbsp;&nbsp;New York, NY 10017 | &nbsp;&nbsp;New York, NY 10017 |
| &nbsp;&nbsp;E-Mail: | bschorr@trianpartners.com |
|  | dmarx@trianpartners.com |
| &nbsp;&nbsp;Attention: | Brian L. Schorr |
|  | Daniel R. Marx |
| &nbsp;&nbsp;with a copy (which shall not constitute notice) to: | &nbsp;&nbsp;with a copy (which shall not constitute notice) to: |
| &nbsp;&nbsp;Debevoise & Plimpton LLP | &nbsp;&nbsp;Debevoise & Plimpton LLP |
| &nbsp;&nbsp;66 Hudson Boulevard | &nbsp;&nbsp;66 Hudson Boulevard |
| &nbsp;&nbsp;New York, NY 10001 | &nbsp;&nbsp;New York, NY 10001 |
| &nbsp;&nbsp;E-Mail: | wdregner@debevoise.com |
|  | efhuang@debevoise.com |
| &nbsp;&nbsp;Attention: | William D. Regner |
|  | Emily F. Huang |

---

<sup>1</sup> Certain information has been omitted and filed separately with the Commission. Confidential treatment has been requested with respect to the omitted portions.

<sup>2</sup> Certain information has been omitted and filed separately with the Commission. Confidential treatment has been requested with respect to the omitted portions.

---

| | | |
|:---|:---|:---|
| &nbsp;&nbsp;Trian Partners AM Fund, L.P. | &nbsp;&nbsp;Trian Partners AM Fund, L.P. | &nbsp;&nbsp;[\*\*\*]<sup>3</sup>% |
| &nbsp;&nbsp;*Notices:* |  |  |
| &nbsp;&nbsp;c/o Trian Fund Management, L.P. | &nbsp;&nbsp;c/o Trian Fund Management, L.P. |  |
| &nbsp;&nbsp;280 Park Avenue |  |  |
| &nbsp;&nbsp;41st Floor |  |  |
| &nbsp;&nbsp;New York, NY 10017 | &nbsp;&nbsp;New York, NY 10017 |  |
| &nbsp;&nbsp;E-Mail: | bschorr@trianpartners.com |  |
|  | dmarx@trianpartners.com |  |
| &nbsp;&nbsp;Attention: | Brian L. Schorr |  |
|  | Daniel R. Marx |  |
| &nbsp;&nbsp;with a copy (which shall not constitute notice) to: | &nbsp;&nbsp;with a copy (which shall not constitute notice) to: |  |
| &nbsp;&nbsp;Debevoise & Plimpton LLP | &nbsp;&nbsp;Debevoise & Plimpton LLP |  |
| &nbsp;&nbsp;66 Hudson Boulevard | &nbsp;&nbsp;66 Hudson Boulevard |  |
| &nbsp;&nbsp;New York, NY 10001 | &nbsp;&nbsp;New York, NY 10001 |  |
| &nbsp;&nbsp;E-Mail: | wdregner@debevoise.com |  |
|  | efhuang@debevoise.com |  |
| &nbsp;&nbsp;Attention: | William D. Regner |  |
|  | Emily F. Huang |  |
| &nbsp;&nbsp;Trian Partners AM Parallel Fund, L.P. | &nbsp;&nbsp;Trian Partners AM Parallel Fund, L.P. | &nbsp;&nbsp;[\*\*\*]<sup>4</sup>% |
| &nbsp;&nbsp;*Notices:* |  |  |
| &nbsp;&nbsp;c/o Trian Fund Management, L.P. | &nbsp;&nbsp;c/o Trian Fund Management, L.P. |  |
| &nbsp;&nbsp;280 Park Avenue |  |  |
| &nbsp;&nbsp;41st Floor |  |  |
| &nbsp;&nbsp;New York, NY 10017 | &nbsp;&nbsp;New York, NY 10017 |  |
| &nbsp;&nbsp;E-Mail: | bschorr@trianpartners.com |  |
|  | dmarx@trianpartners.com |  |
| &nbsp;&nbsp;Attention: | Brian L. Schorr |  |
|  | Daniel R. Marx |  |
| &nbsp;&nbsp;with a copy (which shall not constitute notice) to: | &nbsp;&nbsp;with a copy (which shall not constitute notice) to: |  |
| &nbsp;&nbsp;Debevoise & Plimpton LLP | &nbsp;&nbsp;Debevoise & Plimpton LLP |  |
| &nbsp;&nbsp;66 Hudson Boulevard | &nbsp;&nbsp;66 Hudson Boulevard |  |
| &nbsp;&nbsp;New York, NY 10001 | &nbsp;&nbsp;New York, NY 10001 |  |
| &nbsp;&nbsp;E-Mail: | wdregner@debevoise.com |  |
|  | efhuang@debevoise.com |  |
| &nbsp;&nbsp;Attention: | William D. Regner |  |
|  | Emily F. Huang |  |
| &nbsp;&nbsp;Total |  | &nbsp;&nbsp;100.00% |

---

<sup>3</sup> Certain information has been omitted and filed separately with the Commission. Confidential treatment has been requested with respect to the omitted portions.

<sup>4</sup> Certain information has been omitted and filed separately with the Commission. Confidential treatment has been requested with respect to the omitted portions.

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 16)**

**JANUS HENDERSON GROUP PLC**

*(Name of Issuer)*

**Ordinary Shares, $1.50 per share par value**

*(Title of Class of Securities)*

**—**

*(CUSIP Number)*

**Brian L. Schorr, Esq.**<br>280 Park Avenue, 41st Floor,<br>New York NY 10017<br>(212) 451-3000

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**03/24/2026**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Nelson Peltz** | Name of reporting person<br>**Nelson Peltz** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**AF** | Source of funds (See Instructions)<br>**AF** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**X1** | Citizenship or place of organization<br>**X1** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**31867800.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**31867800.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**31867800.00** | Aggregate amount beneficially owned by each reporting person<br>**31867800.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**20.7%** | Percent of class represented by amount in Row (11)<br>**20.7%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Comment for Reporting Person:** The percentage calculated in Row 13 is based on 154,075,608 Ordinary Shares, $1.50 per share par value ("Ordinary Shares") of Janus Henderson Group plc, a company incorporated and registered in Jersey (the "Issuer"), outstanding as of March 9, 2026, as reported by the Issuer in the Defintive Proxy Statement on Schedule 14A filed with the Securities and Exchange Commission (the "SEC") on March 11, 2026 (the "Definitive Proxy Statement").

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Peter W. May** | Name of reporting person<br>**Peter W. May** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**AF** | Source of funds (See Instructions)<br>**AF** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**X1** | Citizenship or place of organization<br>**X1** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**31867800.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**31867800.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**31867800.00** | Aggregate amount beneficially owned by each reporting person<br>**31867800.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**20.7%** | Percent of class represented by amount in Row (11)<br>**20.7%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Comment for Reporting Person:** The percentage calculated in Row 13 is based on 154,075,608 Ordinary Shares of the Issuer outstanding as of March 9, 2026, as reported by the Issuer in the Definitive Proxy Statement.

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**TRIAN FUND MANAGEMENT, L.P.** | Name of reporting person<br>**TRIAN FUND MANAGEMENT, L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**AF** | Source of funds (See Instructions)<br>**AF** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**X1** | Citizenship or place of organization<br>**X1** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**31867800.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**31867800.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**31867800.00** | Aggregate amount beneficially owned by each reporting person<br>**31867800.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**20.7%** | Percent of class represented by amount in Row (11)<br>**20.7%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

**Comment for Reporting Person:** The percentage calculated in Row 13 is based on 154,075,608 Ordinary Shares of the Issuer outstanding as of March 9, 2026, as reported by the Issuer in the Definitive Proxy Statement.

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Trian Fund Management GP, LLC** | Name of reporting person<br>**Trian Fund Management GP, LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**AF** | Source of funds (See Instructions)<br>**AF** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**X1** | Citizenship or place of organization<br>**X1** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**31867800.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**31867800.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**31867800.00** | Aggregate amount beneficially owned by each reporting person<br>**31867800.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**20.7%** | Percent of class represented by amount in Row (11)<br>**20.7%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

**Comment for Reporting Person:** The percentage calculated in Row 13 is based on 154,075,608 Ordinary Shares of the Issuer outstanding as of March 9, 2026, as reported by the Issuer in the Definitive Proxy Statement.

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Trian Partners AM Holdco II, Ltd.** | Name of reporting person<br>**Trian Partners AM Holdco II, Ltd.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**CAYMAN ISLANDS** | Citizenship or place of organization<br>**CAYMAN ISLANDS** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**31867800.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**31867800.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**31867800.00** | Aggregate amount beneficially owned by each reporting person<br>**31867800.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**20.7%** | Percent of class represented by amount in Row (11)<br>**20.7%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

**Comment for Reporting Person:** The percentage calculated in Row 13 is based on 154,075,608 Ordinary Shares of the Issuer outstanding as of March 9, 2026, as reported by the Issuer in the Definitive Proxy Statement.

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Ordinary Shares, $1.50 per share par value

**(b) Name of Issuer:**
JANUS HENDERSON GROUP PLC

**(c) Address of Issuer's Principal Executive Offices:**
201 Bishopsgate, London, X0, EC2M 3AE

This Amendment No. 16 ("Amendment No. 16") amends and supplements the Schedule 13D filed with the SEC on October 2, 2020 as amended by Amendment No. 1, filed on May 12, 2021, as amended by Amendment No. 2 filed on May 19, 2021, as amended by Amendment No. 3 filed on July 19, 2021, as amended by Amendment No. 4 filed on October 4, 2021, as amended by Amendment No. 5 filed on November 16, 2021, as amended by Amendment No. 6 filed on December 13, 2021, as amended by Amendment No. 7 filed on January 6, 2022, as amended by Amendment No. 8 filed on February 1, 2022, as amended by Amendment No. 9 filed on March 9, 2022, as amended by Amendment No. 10 filed on March 31, 2022, as amended by Amendment No. 11 filed on November 15, 2022, as amended by Amendment No. 12 filed on June 2, 2023, as amended by Amendment No. 13 filed on May 2, 2025, as amended by Amendment No. 14 filed on October 27, 2025, and as amended by Amendment No. 15 filed on December 22, 2025 (as amended, the "Schedule 13D"), relating to the Ordinary Shares of the Issuer. The address of the principal executive office of the Issuer is 201 Bishopsgate, London, EC2M 3AE United Kingdom.

Capitalized terms not defined herein shall have the meaning ascribed to them in the Schedule 13D. Except as set forth herein, the Schedule 13D is unmodified.

**Item 4. Purpose of Transaction**

Item 4 of the Schedule 13D is hereby amended and supplemented to include the following information to the end therof:

Amendment to Agreement and Plan of Merger

On March 24, 2026, the Issuer entered into Amendment No. 1 to the Agreement and Plan of Merger (the "Amendment") with Jupiter Company Limited, a company incorporated in Jersey and an affiliate of the Reporting Persons ("Parent"), and Jupiter Merger Sub Limited, a company incorporated in Jersey and a wholly owned subsidiary of Parent and an affiliate of the Reporting Persons ("Merger Sub"), which amends the previously announced Agreement and Plan of Merger, dated as of December 21, 2025 (the "Original Merger Agreement" and, the Original Merger Agreement as amended, supplemented and otherwise modified by the Amendment, the "Amended Merger Agreement"), pursuant to which Merger Sub will merge with and into the Issuer (the "Merger") in accordance with the Companies (Jersey) Law 1991, with the Issuer continuing as the surviving company and a wholly owned subsidiary of Parent. Capitalized terms used but not defined herein shall have the meanings ascribed to such terms in the Amended Merger Agreement.

Under the terms of the Amendment, the Issuer, Parent and Merger Sub have agreed, as compared to the Original Merger Agreement and among other things, to:

    i. increase the cash consideration to be paid by Parent for each Ordinary Share issued and outstanding immediately prior to the Effective Time (except for shares held by Parent and as otherwise provided in the Amended Merger Agreement) from $49.00 to $52.00 per Ordinary Share in cash, without interest;

    ii. modify the amount payable by the Issuer if either Parent or the Issuer terminates the Amended Merger Agreement because of the failure to obtain the Required Company Vote from a reimbursement of certain fees and expenses actually incurred by or on Parent's behalf, not to exceed $111,420,000, to a fixed payment of $118,200,000 (the "Expense Reimbursement Payment");

    iii. increase the fees payable by the Issuer upon termination of the Amended Merger Agreement under specified circumstances (including if the Issuer terminates the Amended Merger Agreement in order to enter into an alternative transaction that constitutes a Superior Proposal), from (a) $297,130,000 to $394,000,000 if the Expense Reimbursement Payment has not been paid or (b) $222,850,000 to $275,800,000 if the Expense Reimbursement Payment has been paid;

    iv. allow the Issuer to declare, set aside or pay a quarterly dividend not to exceed $1.00 per Ordinary Share beginning with fiscal quarters commencing on or after July 1, 2026, with declaration and payment dates consistent with past practice, and subject to the prior satisfaction or waiver by Parent of certain conditions, including (but not limited to) receipt of the (a) Required Company Vote to approve the Merger and (b) required Client Consent Percentage; and

    v. allow Parent to, following receipt of the Required Company Vote and subject to compliance with Applicable Law, make available to employees of the Issuer capacity for rollover and other equity purchase and/or participation opportunities, such employees to be identified based on their expressed interest and in consultation with senior management of the Issuer, provided that no such opportunity shall create any obligation or other liability of the Issuer prior to the Closing.

Amended and Restated Equity Commitment Letter

Concurrently with the execution of the Amendment, Parent delivered an amended and restated equity commitment letter between Parent and the equity investors party thereto, including, but not limited to, affiliates of certain of the Reporting Persons, (collectively, the "Equity Investors"), pursuant to which the Equity Investors have committed, subject to the terms and conditions contained therein, to invest in Parent, directly or indirectly, the amount set forth therein (the "A&R Equity Commitment Letter"). The Issuer is an express third-party beneficiary of the A&R Equity Commitment Letter and is entitled to specifically enforce the obligations of the Equity Investors, on the terms and subject to the conditions set forth therein.

The information disclosed in this Item 4 does not purport to be a complete statement of the respective parties' rights and obligations under each of the Amendment, the Amended Merger Agreement and the A&R Equity Commitment Letter, as applicable, and is qualified in its entirety by reference to the Amendment and the A&R Equity Commitment Letter, copies of which are attached as Exhibits 12 and 13, respectively, and which are incorporated herein by reference in their entirety, and by reference to the Original Merger Agreement, a copy of which is attached as Exhibit 9 to Amendment 15 to the Schedule 13D filed by the Reprting Persons with the SEC on December 22, 2025 and which is incorporated herein by reference in its entirety. These agreements contain representations, warranties and covenants that the respective parties made to each other as of the date of each agreement or other specific dates. The assertions embodied in those representations, warranties and covenants were made for purposes of the contract among the respective parties and are subject to important qualifications and limitations agreed to by the parties in connection with negotiating such agreement. Each agreement has been attached to provide investors with information regarding its terms and is not intended to provide any other factual information about the Issuer, Parent or any other party to these agreements or any related agreement. Investors and security holders are not third-party beneficiaries under any of the Amendment, the Amended Merger Agreement or the A&R Equity Commitment Letter, and should not rely on the representations, warranties, covenants and agreements, or any descriptions thereof, as characterizations of the actual state of facts or condition of any party to any such agreements. Moreover, information concerning the subject matter of the representations and warranties may change after the date of any of the Amendment, the Amended Merger Agreement or the A&R Equity Commitment Letter, which subsequent information may or may not be fully reflected in the Issuer's or Parent's public disclosures. None of the Amendment, the Amended Merger Agreement or the A&R Equity Commitment Letter should be read alone, but should instead be read in conjunction with the other information regarding the parties to such agreements, including but not limited to, the Issuer and Parent, and the transactions contemplated by such agreements that are contained in and/or attached to, as applicable, the Definitive Proxy Statement and the Schedule 13E-3 filed by the Issuer and affiliates of Parent, as well as in the other filings that the Issuer or affiliates of Parent may make with the SEC.

**Item 5. Interest in Securities of the Issuer**

**(a)**
Item 5(a) is hereby amended and restated in its entirety as follows:

The responses of the Reporting Persons to rows (11) through (13) of the cover pages of this Schedule 13D (including, but not limited to, footnotes to such information) are incorporated herein by reference. As of 4:00 pm, New York City time, on March 24, 2025, the Reporting Persons beneficially owned 31,867,800 Ordinary Shares, representing approximately 20.7% of the Issuer's outstanding Ordinary Shares (calculated based on a total of 154,075,608 Ordinary Shares of the Issuer outstanding as of March 9, 2026, as reported by the Issuer in its Defintive Proxy Statement).

**(b)**
Item 5(b) is hereby amended and restated in its entirety as follows:

The responses of the Reporting Persons to rows (7) through (10) of the cover pages of this Statement (including, but not limited to, footnotes to such information) are incorporated herein by reference. Trian Partners AM Holdco II, Ltd. ("Trian AM Holdco") beneficially and directly owns and has sole voting power and sole dispositive power with regard to 31,867,800 Ordinary Shares, except to the extent that other Reporting Persons as described in this Item 5(b) may be deemed to have shared voting power and shared dispositive power with regard to such Ordinary Shares.

Each of Trian Fund Management, L.P. ("Trian Management"), Trian Fund Management GP, LLC ("Trian Management GP"), Nelson Peltz and Peter W. May, by virtue of their relationships with Trian AM Holdco (as discussed in Item 2 above), may be deemed to have shared voting power and shared dispositive power with regard to, and therefore may be deemed to beneficially own (as that term is defined in Rule 13d-3), the Ordinary Shares that Trian AM Holdco directly and beneficially owns. Each of Trian Management, Trian Management GP, Nelson Peltz and Peter W. May disclaim beneficial ownership of such Ordinary Shares for all other purposes.

Each of the Reporting Persons and Massachusetts Mutual Life Insurance Company ("MassMutual") may be deemed to be members of a "group" for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended. MassMutual has filed a separate Schedule 13D filing to report the Ordinary Shares that it may be deemed to beneficially own. The Reporting Persons expressly disclaim any beneficial ownership of Ordinary Shares held directly by MassMutual and such shares are not the subject of this Schedule 13D.

**(c)**
Item 5(c) is hereby amended and supplemented by adding the following at the end thereof:

Except as set forth in Items 3, 4 and 6, which information is incorporated herein by reference, there have been no new transactions by the Reporting Persons during the sixty days preceding the filing of this Amendment No. 16.

**Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.**

Item 6 of the Schedule 13D is hereby supplemented to incorporate by reference the information set forth in Item 4 above.

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Nelson Peltz

**Signature:** /s/ Nelson Peltz

**Name/Title:** Nelson Peltz

**Date:** 03/24/2026

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Peter W. May

**Signature:** /s/ Peter W. May

**Name/Title:** Peter W. May

**Date:** 03/24/2026

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** TRIAN FUND MANAGEMENT, L.P.

**Signature:** /s/ Peter W. May

**Name/Title:** Member of the General Partner of the Reporting Person

**Date:** 03/24/2026

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Trian Fund Management GP, LLC

**Signature:** /s/ Peter W. May

**Name/Title:** Member

**Date:** 03/24/2026

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Trian Partners AM Holdco II, Ltd.

**Signature:** /s/ Peter W. May

**Name/Title:** Director

**Date:** 03/24/2026