144 0001345471 XXXXXXXX LIVE 0001274173 Janus Henderson Group PLC 001-38103 201 Bishopsgate London X0 EC2M3AE 44-2078181818 TRIAN FUND MANAGEMENT, L.P. Owner Director Common Stock J.P. Morgan Securities

277 Park Avenue New York NY 10172

6213418 321233711 154075608 05/12/2026 NYSE Common Stock 05/15/2020 Open market purchases and exercises of put/call options N/A for open market purchases; Morgan Stanley for put/call option exercises N 6213418 05/15/2020 Cash Y Trian Fund Management, L.P. (TFM) is the investment manager of certain funds which primarily hold publicly traded securities that are selling shares for portfolio management purposes. The shares proposed to be sold were acquired and paid for between 05/15/2020 and 04/04/2022, and may be sold on or after 5/12/2026 for portfolio management purposes. As contemplated by the Voting and Rollover Agreement dated as of December 21, 2025, an affiliate of TFM will roll over at least 24,750,000 shares of the Issuer in connection with the closing of the previously announced acquisition of the Issuer by TFM and its affiliated funds, and General Catalyst and its affiliated funds. Progress toward closing of the acquisition is continuing, with shareholders approving the transaction on April 16, 2026. The acquisition is expected to close in mid-2026, subject to customary closing conditions, including receipt of applicable regulatory approvals and client consents. 05/12/2026 Daniel R. Marx, General Counsel