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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."}],"balance_after":262,"derivative":{"underlying":"Common Stock","underlying_shares":262},"source":{"system":"sec-edgar","filing":"0001127602-25-020600","document":"form4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1004434/000112760225020600/form4.xml","form_type":"4"}},{"id":1064547,"issuer":{"id":3556,"kind":"organization","name":"AFFILIATED MANAGERS GROUP, INC.","symbol":"AMG"},"owners":[{"id":62123,"kind":"person","name":"Alvingham Karen L.","position":1,"cik":"0001726148","reported_name":"Alvingham Karen L.","relationship":{"director":true}}],"security":"Common Stock","published_at":"2025-08-18T21:11:52.000Z","date":"2025-08-15","kind":"tax_withholding","planned":false,"acquired":false,"shares":84,"price":218.7,"value":18370.8,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F2","text":"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."}],"balance_after":11865,"source":{"system":"sec-edgar","filing":"0001127602-25-020600","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1004434/000112760225020600/form4.xml","form_type":"4"}},{"id":1064546,"issuer":{"id":3556,"kind":"organization","name":"AFFILIATED MANAGERS GROUP, INC.","symbol":"AMG"},"owners":[{"id":62123,"kind":"person","name":"Alvingham Karen L.","position":1,"cik":"0001726148","reported_name":"Alvingham Karen L.","relationship":{"director":true}}],"security":"Common Stock","published_at":"2025-08-18T21:11:52.000Z","date":"2025-08-15","kind":"exercise","planned":false,"acquired":true,"shares":1092,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects the vesting of previously reported awards. Awards vest 2022-2027."}],"balance_after":11949,"source":{"system":"sec-edgar","filing":"0001127602-25-020600","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1004434/000112760225020600/form4.xml","form_type":"4"}},{"id":1064551,"issuer":{"id":3556,"kind":"organization","name":"AFFILIATED MANAGERS GROUP, INC.","symbol":"AMG"},"owners":[{"id":22480,"kind":"person","name":"FRANQUI ANNETTE","position":1,"cik":"0001849146","reported_name":"FRANQUI ANNETTE","relationship":{"director":true}}],"security":"Stock Units","published_at":"2025-08-18T21:08:59.000Z","date":"2025-08-15","kind":"exercise","planned":false,"acquired":false,"shares":664,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Reflects the vesting of a previously reported award. Award vested in 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"Reflects the vesting of a previously reported award. Award vested in 2025."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F1","text":"Reflects the vesting of a previously reported award. Award vested in 2025."}],"balance_after":1025,"derivative":{"underlying":"Common Stock","underlying_shares":664},"source":{"system":"sec-edgar","filing":"0001127602-25-020599","document":"form4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1004434/000112760225020599/form4.xml","form_type":"4"}}],"next_cursor":"2025-08-18T21:08:59.000000Z,1064551"}