SCHEDULE 13D/A

JANUS HENDERSON GROUP PLC

Ordinary Shares, $1.50 per share par value · CUSIP: G4474Y214

Event date: 2025-12-21

Reporting persons may disclose overlapping interests. Their amounts are shown individually and are not added into a filing total.

Filing-level shares

Unavailable

Percent of class

Unavailable

• Nelson Peltz

  Shares: 31,867,800.00 · Class: 20.6%

• Peter W. May

  Shares: 31,867,800.00 · Class: 20.6%

• TRIAN FUND MANAGEMENT, L.P.Reported CIK 0001345471

  Shares: 31,867,800.00 · Class: 20.6%

• Trian Fund Management GP, LLC

  Shares: 31,867,800.00 · Class: 20.6%

• Trian Partners AM Holdco II, Ltd.

  Shares: 31,867,800.00 · Class: 20.6%

Amounts are as disclosed in this filing. Schedule type alone does not establish investment intent.