AMG (NYSE: AMG) director logs stock unit vesting, new grants and tax share surrender

Rhea-AI Filing Summary

AFFILIATED MANAGERS GROUP, INC. director Karen L. Alvingham reported equity compensation activity involving stock units and common stock. On March 5, 2026, 867 stock units vested and converted into 867 shares of common stock as part of previously reported awards that vest from 2023 to 2026.

She also received new grants of 171 stock units that vest in full on March 5, 2027, and 98 deferred stock units tied to cash fees she elected to defer under the company’s deferred compensation plan. Each stock or deferred stock unit represents one share of common stock at settlement.

In a related move, 67 shares of common stock were automatically surrendered to the company at $299.18 per share to satisfy tax withholding obligations tied to the vesting, rather than an open-market sale.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Alvingham Karen L.

(Last) (First) (Middle)

C/O AFFILIATED MANAGERS GROUP, INC.

777 SOUTH FLAGLER DRIVE

(Street)

WEST PALM BEACH FL 33401

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
AFFILIATED MANAGERS GROUP, INC. [ AMG ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
03/05/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/05/2026		M		867	A	$0(1)	13,110	D
Common Stock	03/05/2026		F		67(2)	D	$299.18	13,043	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Units	(1)	03/05/2026		M			867	(1)	(1)	Common Stock	867	$0	3,709(3)	D
Stock Units	(4)	03/05/2026		A		171		(4)	(4)	Common Stock	171	$0	171	D
Deferred Stock Units	(5)	03/05/2026		A		98		(5)	(5)	Common Stock	98	$0	98	D

Explanation of Responses:

1. Reflects the vesting of previously reported awards. Awards vest 2023-2026.

2. 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.

3. Inclusive of previously reported deferred stock units.

4. 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.

5. 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.

	/s/ Kavita Padiyar, Attorney-in-Fact	03/09/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transactions did AMG director Karen L. Alvingham report?

Karen L. Alvingham reported vesting and conversion of 867 stock units into common stock, new grants of 171 stock units and 98 deferred stock units, plus an automatic surrender of 67 shares to cover tax withholding obligations related to the vesting event.

Did Karen L. Alvingham buy or sell AMG common stock in the open market?

The filing does not show open-market buying or selling. Shares involved came from vesting and equity awards, and 67 shares of common stock were automatically surrendered back to the company solely to satisfy tax withholding obligations, not as a discretionary market sale.

What are the terms of Karen L. Alvingham’s new AMG stock unit grant?

She received 171 stock units, each representing one share of AMG common stock. According to the disclosure, these stock units vest in full on March 5, 2027, providing time-based equity compensation tied to continued service on the company’s board of directors.

How do the AMG deferred stock units reported by Karen L. Alvingham work?

The 98 deferred stock units reflect cash director fees she elected to defer. These amounts are notionally invested in a fund tracking AMG common stock, with each deferred stock unit equal to one share, distributable in common stock when she leaves the board of directors.

Why were 67 AMG shares surrendered by Karen L. Alvingham?

The 67 common shares were automatically surrendered to AMG at $299.18 per share. This was done to satisfy tax withholding obligations arising from the vesting of previously granted stock unit awards, rather than representing a voluntary open-market sale of shares.

How many AMG shares and units does Karen L. Alvingham hold after these transactions?

After the March 5, 2026 transactions, she directly holds 13,043 shares of AMG common stock, 3,709 stock units, and 98 deferred stock units, based on the share balances following each reported transaction in the Form 4 filing’s ownership tables and footnotes.