AFFILIATED MANAGERS GROUP, INC. 10-Q

Item 5. Other Information The Company’s Board of Directors has amended and restated the Company’s By-laws, effective as of the date of this Quarterly Report on Form 10-Q, to add references to “Managing Directors” in Sections 1 and 11 of Article III, in light of the Company’s recent organizational evolution and new officer titles. The summary above is qualified in its entirety by the text of the amended and restated By-laws, which are attached as Exhibit 3.1 to this Quarterly Report on Form 10-Q. Item 6. Exhibits The exhibits are listed on the Exhibit Index and are included elsewhere in this Quarterly Report on Form 10-Q. 32 Table of Contents EXHIBIT INDEX Exhibit No. Description 3.1 Amended and Restated By-Laws* 10.1† Form of Restricted Stock Unit Award Agreement pursuant to Affiliated Managers Group, Inc. 2020 Equity Incentive Plan* 10.2† Form of Stock Option Award Agreement pursuant to Affiliated Managers Group, Inc. 2020 Equity Incentive Plan* 22 Subsidiary Issuers of Guaranteed Securities* 31.1 Certification of Registrant’s Chief Executive Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002* 31.2 Certification of Registrant’s Chief Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002* 32.1 Certification of Registrant’s Chief Executive Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002** 32.2 Certification of Registrant’s Chief Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002** 101 The following financial statements from the Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2021 are filed herewith, formatted in XBRL (Inline eXtensible Business Reporting Language): (i) the Consolidated Statements of Income for the three-month periods ended March 31, 2021 and 2020, (ii) the Consolidated Statements of Comprehensive Income for the three-month periods ended March 31, 2021 and 2020, (iii) the Consolidated Balance Sheets at March 31, 2021 and December 31, 2020, (iv) the Consolidated Statements of Changes in Equity for the three-month periods ended March 31, 2021 and 2020, (v) the Consolidated Statements of Cash Flows for the three-month periods ended March 31, 2021 and 2020, and (vi) the Notes to the Consolidated Financial Statements 104 The cover page from the Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2020, formatted in XBRL (Inline eXtensible Business Reporting Language) and contained in Exhibit 101 † Indicates a management contract or compensatory plan * Filed herewith ** Furnished herewith 33 Table of Contents SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. AFFILIATED MANAGERS GROUP, INC. (Registrant) May 7, 2021 /s/ THOMAS M. WOJCIK Thomas M. Wojcik on behalf of the Registrant as Chief Financial Officer (and also as Principal Financial and Principal Accounting Officer) 34 Table of Contents QuickLinks PART I—FINANCIAL INFORMATION Item 1. Financial Statements AFFILIATED MANAGERS GROUP, INC. CONSOLIDATED STATEMENTS OF INCOME (in millions, except per share data) (unaudited) AFFILIATED MANAGERS GROUP, INC. CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (in millions) (unaudited) AFFILIATED MANAGERS GROUP, INC. CONSOLIDATED CONDENSED BALANCE SHEETS (in millions) (unaudited) AFFILIATED MANAGERS GROUP, INC. CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (in millions) (unaudited) AFFILIATED MANAGERS GROUP, INC. CONSOLIDATED STATEMENTS OF CASH FLOWS (in millions) (unaudited) AFFILIATED MANAGERS GROUP, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations Item 3. Quantitative and Qualitative Disclosures About Market Risk Item 4. Controls and Procedures PART II—OTHER INFORMATION Item 2. Unregistered Sales of Equity Securities and Use of Proceeds Item 6. Exhibits EXHIBIT INDEX SIGNATURES