[Form 4] Affiliated Managers Group Insider Trading Activity

Rhea-AI Filing Summary

Affiliated Managers Group (AMG) Form 4 shows insider transactions by Jay C. Horgen, who serves as CEO and a director. On 08/12/2025 he exercised 75,000 employee stock options with an exercise price of $74.49, receiving 75,000 common shares. The filing also records a disposition of 45,607 shares at $219.70. After these transactions Mr. Horgen beneficially owned 529,929 shares directly and 34,058 shares indirectly through family trusts, with a reported total of 150,000 shares from options held directly following execution.

Insights

Financial Analyst

TL;DR: Insider exercised options and sold a portion of stock, increasing direct shareholdings while monetizing some position.

The Form 4 documents an option exercise of 75,000 shares at $74.49 and a concurrent sale of 45,607 shares at $219.70 on 08/12/2025. Exercising options at a substantially lower strike and selling at a higher market price is a common liquidity action by executives. The filing shows meaningful direct ownership (529,929 shares) plus indirect holdings (34,058 by family trusts), which indicates continued alignment with shareholders while enabling cash realization on part of the position.

Corporate Governance Expert

TL;DR: Transactions are routine insider activity; disclosure appears complete and signed by Attorney-in-Fact.

The report is signed via attorney-in-fact and lists Mr. Horgen as both CEO and director, with clear coding for an option exercise (code M) and a sale (code F). Ownership figures before and after the transactions are provided and indirect ownership via family trusts is disclosed. From a governance perspective the filing meets Section 16 reporting standards and provides investors transparency on insider actions.

Insider Trade Summary

75,000 shares exercised/converted

Mixed 4 txns

Insider Horgen Jay C.

Role Chief Executive Officer

Type	Security	Shares	Price	Value
Exercise	Employee Stock Option (Right to Buy)	75,000	$0.00	--
Exercise	Common Stock	75,000	$74.49	$5.59M
Tax Withholding	Common Stock	45,607	$219.70	$10.02M
holding	Common Stock	--	--	--

Holdings After Transaction: Employee Stock Option (Right to Buy) — 150,000 shares (Direct); Common Stock — 529,929 shares (Direct); Common Stock — 34,058 shares (Indirect, By Family Trusts)

Footnotes (1)

Form 4 Insider Transactions: What Each Field Means →

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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^*

Horgen Jay C.

(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
X	Officer (give title below)		Other (specify below)
	Chief Executive Officer

3. Date of Earliest Transaction (Month/Day/Year)
08/12/2025

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	08/12/2025		M		75,000	A	$74.49	529,929	D
Common Stock	08/12/2025		F		45,607	D	$219.7	484,322	D
Common Stock								34,058	I	By Family Trusts

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
Employee Stock Option (Right to Buy)	$74.49	08/12/2025		M			75,000	08/15/2024	08/15/2026	Common Stock	75,000	$0	150,000	D

Explanation of Responses:

	/s/ Kavita Padiyar, Attorney-in-Fact	08/14/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.