Institutional Stake Radar — 13D/13G

Item 4 of the Schedule 13D is hereby amended and supplemented by adding the following: On June 30, 2026, the transactions contemplated by the Agreement and Plan of Merger, dated December 21, 2025 (as amended by Amendment No. 1 to the Agreement and Plan of Merger, dated as of March 24, 2026 and the side letter agreement, dated as of June 16, 2026, the "Merger Agreement"), by and among Parent, Merger Sub and the Issuer were consummated. Pursuant to the Merger Agreement, Merger Sub merged with and into the Issuer (the "Merger"), and the Issuer continued as the surviving company and converted to a private limited company incorporated under the laws of Jersey and changed its name from "Janus Henderson Group plc" to "Janus Henderson Group Ltd.". At the effective time of the Merger (the "Effective Time"), each ordinary share, par value $1.50 per share, of the Issuer (an "Ordinary Share" and collectively, the "Ordinary Shares") outstanding immediately prior to the Effective Time (except for Ordinary Shares held by Parent and as otherwise provided in the Merger Agreement) was converted into the right to receive $52.00 per share in cash, without interest (the "Merger Consideration"). Immediately prior to the Effective Time, Trian Partners AM Holdco II, Ltd. and certain other funds affiliated with Trian Fund Management, L.P. ("Trian") contributed 25,136,205 Ordinary Shares to Jupiter Topco LLC ("Topco") in exchange for equity interests of Topco of equivalent value. All other Ordinary Shares beneficially owned by the Reporting Persons were converted into the right to receive the Merger Consideration. Also immediately prior to the Effective Time, each member of the Issuer's board of directors, including Brian Baldwin and Josh Frank, each a Partner at Trian, resigned from and ceased serving on the Issuer's board of directors. As a result of the Merger, the Ordinary Shares will no longer be listed on The New York Stock Exchange and will be deregistered under Section 12(b) of …

The Reporting Persons file the long form Schedule 13D pursuant to Section 13d-1 of the Securities Exchange Act of 1934 (the "Act") even though they may be technically eligible to file the short form Schedule G. Because the Reporting Persons may regularly communicate with the Issuer's management, filing the Schedule 13D ensures that these conversations are compliant with the reporting obligations under the Exchange Act.

No material changes from the Schedule 13D amendment filed by the Reporting Persons on October 23, 2024.

The response to Item 3 of this Schedule 13D is incorporated by reference herein. On June 6, 2026, the Issuer, Treeline Biosciences, Inc., a Delaware corporation ("Treeline"), and Siri Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of the Issuer ("Merger Sub"), entered into an Agreement and Plan of Merger and Reorganization (the "Merger Agreement"), pursuant to which, among other matters, and subject to the satisfaction or waiver of the conditions set forth in the Merger Agreement, Merger Sub will merge with and into Treeline, with Treeline continuing as a wholly owned subsidiary of the Issuer and the surviving corporation of the merger (the "Merger"). Upon the terms and subject to the conditions set forth in the Merger Agreement, at the effective time of the Merger ("Effective Time"), each share of capital stock of Treeline will be converted into the right to receive a number of shares of Common Stock in accordance with the Exchange Ratio (as defined in the Merger Agreement). Also on June 6, 2026, in connection with the Merger Agreement, the Issuer, Treeline and Merger Sub entered into a voting agreement (the "Voting Agreement") with VGOP and VGOD. Pursuant to the Voting Agreement, VGOP and VGOD have agreed, among other things, subject to the terms and conditions thereof, to: (i) vote their beneficially owned securities of the Issuer: (1) in favor of the approval of (i) the issuance of Common Stock to holders of Treeline stock pursuant to the Merger Agreement, (ii) an amendment to the Issuer's charter pursuant to which the name of Issuer will be changed to "Treeline Biosciences Holdings, Inc.", (iii) a reverse stock split of all outstanding shares of Common Stock at a reverse stock split ratio mutually agreed to by Treeline and the Issuer, and (iv) the adoption of the Post-Closing Equity Incentive Plan and Post-Closing ESPP (each as defined in the Merger Agreement); (2) in favor of any proposal to adjourn to a later date if there is not a q…