Horgen Jay C. 4

What Happened

• Jay C. Horgen, CEO of Affiliated Managers Group (AMG), had equity awards vest and exercised/converted derivatives on March 5, 2026. The Form 4 shows acquisitions of 17,563 shares from an exercise/conversion (code M), 27,260 shares from a grant/award (code A), and an additional 8,544 award shares (code A, derivative). To satisfy tax withholding obligations, 18,333 shares were automatically surrendered/disposed (code F) at $299.18 per share, producing $5,484,867. The Form 4 also shows a derivative disposition of 17,563 shares (M).

Key Details

• Transaction date: March 5, 2026; Form 4 filed March 9, 2026 (filed on time under the two-business-day rule).
• Acquisitions reported: 17,563 shares (exercise/conversion, M), 27,260 shares (award, A), 8,544 shares (award, A — derivative); listed price $0 on the filing for those acquisitions.
• Dispositions reported: 18,333 shares surrendered to cover tax withholding at $299.18 each = $5,484,867; also a derivative disposition of 17,563 shares (reported $0).
• Shares owned after the transactions: not specified in the provided summary.
• Relevant footnotes: F1 = vesting of previously reported awards (vesting 2023–2029); F3 = March 2023 performance award settled after performance conditions; F4 = automatic share surrender to satisfy tax withholding; F5 = certain award vests in equal installments in 2027–2030; F2 notes a separate transfer of 200,000 shares to a grantor retained annuity trust.

Context

• This looks like a routine exercise/settlement of awards with an automatic share surrender to cover tax obligations (a cashless-style settlement), rather than an open‑market sale for investment purposes. Such tax-withholding dispositions are common and don’t necessarily indicate the insider’s view on the stock.