Karen L. Alvingham - 05 Mar 2026 Form 4 Insider Report for AFFILIATED MANAGERS GROUP, INC. (AMG)

Role: Director
Signature: /s/ Kavita Padiyar, Attorney-in-Fact
Issuer symbol: AMG
Transactions as of: 05 Mar 2026
Net transactions value: $0
Form type: 4
Filing time: 09 Mar 2026, 17:44:29 UTC
Previous filing: 12 Nov 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Alvingham Karen L.	Director	C/O AFFILIATED MANAGERS GROUP, INC., 777 SOUTH FLAGLER DRIVE, WEST PALM BEACH	/s/ Kavita Padiyar, Attorney-in-Fact	09 Mar 2026	0001726148

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	AMG	Common Stock	Options Exercise		+867	+7.1%	$0.000000^*	13,110	05 Mar 2026	Direct	F1
transaction	AMG	Common Stock	Tax liability		-67	-0.51%	$299.18^*	13,043	05 Mar 2026	Direct	F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	AMG	Stock Units	Options Exercise		-867	-19%	$0.000000^*	3,709	05 Mar 2026	Common Stock	867		Direct	F1, F3
transaction	AMG	Stock Units	Award		+171		$0.000000^*	171	05 Mar 2026	Common Stock	171		Direct	F4
transaction	AMG	Deferred Stock Units	Award		+98		$0.000000^*	98	05 Mar 2026	Common Stock	98		Direct	F5

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Reflects the vesting of previously reported awards. Awards vest 2023-2026.
F2	Reflects the automatic surrender of shares of common stock to the Company to satisfy tax withholding obligations related to the vesting of the awards described above.
F3	Inclusive of previously reported deferred stock units.
F4	Each stock unit represents a right to receive one share of the Company's common stock upon vesting. The stock units vest in full on March 5, 2027.
F5	Reflects cash fees that the director has elected to defer under the Company's deferred compensation plan, which are notionally invested in a measurement fund tracking the Company's common stock during the deferral period. Each deferred stock unit is equal to one share of the Company's common stock, and becomes distributable in common stock upon the reporting person's separation from service as a member of the Board of Directors of the Company.