SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, DC 20549

FORM 10-Q

(Mark One)

Commission File Number 001-13459

Affiliated Managers Group, Inc.
(Exact name of registrant as specified in its charter)

600 Hale Street, Prides Crossing, Massachusetts 01965
(Address of principal executive offices)

(617) 747-3300
(Registrant's telephone number, including area code)

        Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ý    No o

        Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes o    No o (Registrant is not subject to the requirements of Rule 405 of Regulation S-T at this time).

        Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or a smaller reporting company. See the definitions of "large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act.

        Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes o    No ý

        There were 41,678,82944,548,728 shares of the registrant's common stock outstanding on August 3, 2009.May 6, 2010.

PART I—FINANCIAL INFORMATION

Item 1.    Financial Statements

AFFILIATED MANAGERS GROUP, INC.

CONSOLIDATED STATEMENTS OF INCOME

(dollars in thousands, except per share data)

(unaudited)

The accompanying notes are an integral part of the Consolidated Financial Statements.

AFFILIATED MANAGERS GROUP, INC.

CONSOLIDATED BALANCE SHEETS

(in thousands)

(unaudited)

The accompanying notes are an integral part of the Consolidated Financial Statements.

AFFILIATED MANAGERS GROUP, INC.

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY

(dollars in thousands)

(unaudited)

The accompanying notes are an integral part of the Consolidated Financial Statements.

AFFILIATED MANAGERS GROUP, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

(unaudited)

The accompanying notes are an integral part of the Consolidated Financial Statements.

AFFILIATED MANAGERS GROUP, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

1. Basis of Presentation

        The consolidated financial statements of Affiliated Managers Group, Inc. ("Company"AMG" or "AMG"the "Company") have been prepared in accordance with accounting principles generally accepted in the United States of America for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States of America for complete financial statements. The year-end condensed balance sheet data was derived from audited financial statements, but does not include all of the disclosures required by accounting principles generally accepted in the United States of America. In the opinion of management, all adjustments considered necessary for a fair statement of the results have been included. All intercompany balances and transactions have been eliminated. All dollar amounts in these notes (except information that is presented on a per share, per security, per note or per contract basis) are stated in thousands, unless otherwise indicated. Certain reclassifications have been made to the prior period's financial statements to conform to the current period's presentation. In this Quarterly Report on Form 10-Q, the Company has included the current quarter operating results of one of its equity method Affiliates (formerly recorded one quarter in arrears, as permitted for equity method investments). This reporting change did not have a material effect on the Company's consolidated financial results. Operating results for interim periods are not necessarily indicative of the results that may be expected for any other period or for the full year. The Company's Annual Report on Form 10-K (as amended, the "Annual Report on Form 10-K") for the fiscal year ended December 31, 20082009 includes additional information about AMG, its operations, its financial position and its accounting policies, and should be read in conjunction with this Quarterly Report on Form 10-Q.

2. Recently Adopted Accounting Standards

        In 2009, the Company adopted several accounting standards that have been retrospectively applied to prior periods, including

•

FASB Staff Position ("FSP") APB 14-1 "Accounting for Convertible Debt Instruments That May Be Settled in Cash Upon Conversion (Including Partial Cash Settlement)" ("APB 14-1");



•

Statement of Financial Accounting Standards ("FAS") No. 141 (revised 2007) "Business Combinations" ("FAS 141R");



•

FAS No. 160 "Non-Controlling Interests in Consolidated Financial Statements, an amendment of ARB No. 51" ("FAS 160"); and



•

Emerging Issues Task Force ("EITF") Topic No. D-98 "Classification and Measurement of Redeemable Securities" ("Topic D-98").

        APB 14-1 requires the Company to bifurcate certain of its convertible debt securities into their theoretical debt and equity components. The Company accretes (as interest expense) the debt components to their principal amounts over the expected life of the debt. As a result of APB 14-1, the Company has reported incremental non-cash interest of approximately $529 and $3,365 for the three months ended June 30, 2008 and 2009, respectively.

        FAS 141R requires the Company to expense acquisition-related professional fees. The Company retrospectively applied FAS 141R to acquisition-related professional fees that were deferred as of December 31, 2008, and, accordingly, the Company's 2008 net income was reduced by $5,902 ($328 and

AFFILIATED MANAGERS GROUP, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

$859 attributable to the three and six months ended June 30, 2008, respectively). The other provisions of FAS 141R will be applied to future acquisitions.

        FAS 160 requires the Company to change the income statement, balance sheet and cash flow presentation of non-controlling interests (previously known as minority interests). Net income (non-controlling interest), which was previously reported as Minority interest (and reduced net income) on the Company's Consolidated Statements of Income, is now included in Net income. The accumulated capital of non-controlling interests, which was previously reported as Minority interest on the Company's Consolidated Balance Sheets, is now reported in Equity. Payments to non-controlling interests, profit distributions and repurchases of Affiliate equity, are now classified as financing activities on the Statements of Cash Flows (previously reported as operating and investing activities, respectively).

        Topic D-98 provides guidance on the reporting of equity securities that are subject to mandatory redemption requirements or whose redemption is outside the control of the issuer. Topic D-98 requires the Company to present the redemption value of its Affiliate equity on its Consolidated Balance Sheets (referred to as "Redeemable non-controlling interests"). Adjustments to Redeemable non-controlling interests are recorded to stockholders' equity.

        The Company adopted several other accounting standards that became effective in the second quarter of 2009, none of which had a material impact on its results of operations or financial position.

3. Senior Bank Debt

        On November 27,In the fourth quarter of 2007, the Company entered into an amended and restated senior credit facility (the "Facility"). During the third quarter of 2008, the Company increased its borrowing capacity to $1,010,000, comprised of a $770,000 revolving credit facility (the "Revolver") and a $240,000 term loan (the "Term Loan"). In the first quarter of 2009, the Company repaid the outstanding balance of the Term Loan ($233,514); the capacity under the Revolver remains at $770,000. The Company pays interest on any outstanding obligations at specified rates (based either on the Eurodollar rate or the prime rate as in effect from time to time) that vary depending on the Company's credit rating. Subject to the agreement of lenders to provide additional commitments, the Company has the option to increase the Facility by up to an additional $175,000.

        The FacilityRevolver, which will mature in February 2012, and contains financial covenants with respect to leverage and interest coverage. The Facility also contains customary affirmative and negative covenants, including limitations on indebtedness, liens, cash dividends and fundamental corporate changes. Borrowings under the Facility are collateralized by pledges of the substantial majority of capital stock or other equity interests owned by the Company. TheAt March 31, 2010, the Company had $170,000 of outstanding borrowings under the FacilityRevolver.

3. Senior Convertible Securities

        The carrying values of $233,514 at December 31, 2008 and no outstanding borrowings at June 30, 2009.the senior convertible securities are as follows:

AFFILIATED MANAGERS GROUP, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

4. Senior Convertible Securities

        Following the Company's adoption of APB 14-1, the carrying values of the senior convertible securities are as follows:

2008 Senior Convertible Notes

        In August 2008, the Company issued $460,000 of senior convertible notes due 2038 ("2008 senior convertible notes"). The 2008 senior convertible notes bear interest at 3.95%, payable semi-annually in cash. In accordance with APB 14-1, theThe Company is accreting the carrying value to the principal amount at maturity using an interest rate of 7.4% (over its expected life of five years), resulting in incremental interest expense for 2009 of approximately $11,205.. Each security is convertible into 7.959 shares of the Company's common stock (at an initial conversion price of $125.65) upon the occurrence of certain events.events, as follows: (i) during any fiscal quarter, if the closing price of the Company's common stock, as measured over a specified time period during the preceding fiscal quarter, is equal to or greater than 130% of the conversion price of the notes on the last day of such preceding fiscal quarter; (ii) during a certain window of time, if the trading price per $1,000 principal amount of the notes for each day during a specified period is less than 98% of the product of the last reported sale price of the Company's common stock and the conversion rate of the notes on such day; (iii) upon the occurrence of specified corporate transactions; (iv) after the notes have been called for redemption; and (v) anytime after February 15, 2038. Upon conversion, the Company may elect to pay orcash, deliver cash, shares of its common stock, or somea combination thereof. The holders of the 2008 senior convertible notes may require the Company to repurchase the notes in August of 2013, 2018, 2023, 2028 and 2033. The Company may redeem the notes for cash (subject to the holdersholders' right to convert) at any time on or after August 15, 2013.

        The 2008 senior convertible notes are considered contingent payment debt instruments under federal income tax regulations. These regulations require the Company to deduct interest in an amount greater than its reported interest expense, which will result in annual deferred tax liabilities of approximately $10,200.$11,200. These deferred tax liabilities will be reclassified directly to stockholders' equity if the Company's common stock is trading above certain thresholds at the time of the conversion of the notes.

Zero Coupon Senior Convertible Notes

        In 2001, the Company issued $251,000 principal amount at maturity of zero coupon senior convertible notes due 2021 ("zero coupon convertible notes"), with each note issued at 90.50% of such principal amount and accreting at a rate of 0.50% per year (the adoption of APB 14-1 did not affect these securities).year. As of June 30, 2009, $50,135March 31, 2010, $50,125 principal amount at maturity remains outstanding. Each security is convertible into 17.429 shares of the Company's common stock (at a current base conversion price of $54.09)$54.28) upon the occurrence of certain events, including the following:as follows: (i) during any fiscal quarter, if the closing price of a share of the Company's common stock, as measured over a specified time period during the preceding fiscal quarter, is moregreater than a specified conversion price over certain periods (initially $62.36 and increasing incrementally at the end of each calendar quarter to $63.08 in April 2021); (ii) if the credit rating assigned by Standard & Poor's to the securities is below BB-; or (iii) if the Company calls the securities for redemption.redemption and (iv) upon the occurrence of specified corporate transactions. The holders may require the Company to repurchase the securities at their accreted value in May 2011 and 2016. If the holders exercise this option in the future, the Company may elect to repurchase the securities with cash, shares of its common stock or somea combination thereof. The Company has the option to redeem the securities for cash at their accreted value. UnderSubject to changes in the termsprice of the indenture governingCompany's common stock, the zero coupon convertible notes a holder may not be convertible in certain future periods.

AFFILIATED MANAGERS GROUP, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

convert such security into common stock by following the conversion procedures in the indenture. Subject to changes in the price of the Company's common stock, the zero coupon convertible notes may be convertible in certain future periods.

5.4. Junior Convertible Trust Preferred Securities

        Following the Company's adoption of APB 14-1, theThe carrying values of the junior convertible trust preferred securities are as follows:

        In 2006, the Company issued $300,000 of junior subordinated convertible debentures due 2036 to a wholly-owned trust simultaneous with the issuance, by the trust, of $291,000 of convertible trust preferred securities to investors. The junior subordinated convertible debentures and convertible trust preferred securities (together, the "2006 junior convertible trust preferred securities") have substantially the same terms.

        The 2006 junior convertible trust preferred securities bear interest at a rate of 5.1% per annum, payable quarterly in cash. In accordance with APB 14-1, theThe Company is accreting the carrying value to the principal amount at maturity using an interest rate of 7.5% (over its expected life of 30 years). The incremental interest expense for 2009 is expected to be $1,036. Each $50 security is convertible, at any time, into 0.333 shares of the Company's common stock, which represents a conversion price of $150 per share (or a 48% premium to the then prevailing share price of $101.45). Upon conversion, investorsholders will receive cash or shares of the Company's common stock (or a combination of cash and common stock) at the election of the Company. The 2006 junior convertible trust preferred securities may not be redeemed by the Company prior to April 15, 2011. On or after April 15, 2011, they may be redeemed if the closing price of the Company's common stock exceeds $195 per share for a specified period of time. The trust's only assets are the junior convertible subordinated debentures. To the extent that the trust has available funds, the Company is obligated to ensure that holders of the 2006 junior convertible trust preferred securities receive all payments due from the trust.

        In October 2007, the Company issued an additional $500,000 of junior subordinated convertible debentures which are due 2037 to a wholly-owned trust simultaneous with the issuance, by the trust, of $500,000 of convertible trust preferred securities to investors. The junior subordinated convertible debentures and convertible trust preferred securities (together, the "2007 junior convertible trust preferred securities") have substantially the same terms. In the fourth quarter of 2008, the Company repurchased $69,180 aggregate principal amount of the 2007 junior convertible trust preferred securities. Following this repurchase, these securities were cancelled and retired.

        The 2007 junior convertible trust preferred securities bear interest at 5.15% per annum, payable quarterly in cash. In accordance with APB 14-1, theThe Company is accreting the discounted amount to the principal amount at maturity using an interest rate of 8.0% (over its expected life of 30 years). The

AFFILIATED MANAGERS GROUP, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

incremental interest expense for 2009 is expected to be $1,288. Each $50 security is convertible, at any time, into 0.25 shares of the Company's common stock, which represents a conversion price of $200 per share (or a 53% premium to the then prevailing share price of $130.77). Upon conversion, investorsholders will receive cash or shares of the Company's common stock (or a combination of cash and common stock) at the election of the Company. The 2007 junior convertible trust preferred securities may not be redeemed by the Company prior to October 15, 2012. On or after October 15, 2012, they may be redeemed if the closing price of the Company's common stock exceeds $260 per share for a specified period of time. The trust's only assets are the 2007 junior convertible subordinated debentures. To the extent that the trust has available funds, the Company is obligated to ensure that holders of the 2007 junior convertible trust preferred securities receive all payments due from the trust.

AFFILIATED MANAGERS GROUP, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

        The 2006 and 2007 junior convertible trust preferred securities are considered contingent payment debt instruments under federal income tax regulations. These regulations require the Company to deduct interest in an amount greater than its reported interest expense, which will result in annual deferred tax liabilities of approximately $8,800.$9,500. These deferred tax liabilities will be reclassified directly to stockholders' equity if the Company's common stock is trading above certain thresholds at the time of the conversion of the notes.

6.5. Forward Equity Sale Agreements

        In May 2008, theThe Company has entered into athree forward equity sale agreementagreements with a major securities firmfirms to sell up to $200,000shares of its common stock (the "May 2008 Agreement"), with the timing of sales in the Company's discretion.(up to $200,000 under each agreement). Under the terms of the May 2008 Agreement,these agreements, the Company can settle forward sales at any time prior to MarchDecember 31, 2010 by issuing shares in exchange for cash. Alternatively,cash or, at the Company may choose to settle forward salesCompany's option, by settling on a net stock or cash basis. TheAs of March 31, 2010, the Company has sold all $200,000 under the May 2008 Agreement$349,330 of forward sales that remain unsettled at a weighted average exercise price of $65.41 and has settled approximately $144,000$57.54.

        A summary of these forward sales through the issuance of approximately 1.8 million shares.

        In May 2009, the Company entered into a secondCompany's forward equity sale agreementagreements is as follows:

6. Income Taxes

        A summary of the provision for income taxes is as follows:

AFFILIATED MANAGERS GROUP, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

7. Income Taxes

        The Company's consolidated income taxes represent taxes on Net Income (controlling interest) as net income attributable to non-controlling interests is not taxed at the corporate level. A summary of the provision for income taxes is as follows:

(1)

Calculated by dividing the Provision for Income Taxes by Income before income taxes, excluding income attributable to non-controlling interests.

        During the quarter ended June 30, 2009, the Company reversed $3,000 of its valuation allowance on state net operating losses upon the adoption by the Commonwealth of Massachusetts of favorable tax regulations. This adjustment reduced the Company's effective tax rate for the three and six months ended June 30, 2009, respectively.

        The components of deferred tax assets and liabilities are as follows:

AFFILIATED MANAGERS GROUP, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

        Deferred tax liabilities are primarily the result of tax deductions for the Company's intangible assets and convertible securities. The Company amortizes most of its intangible assets for tax purposes only, reducing its tax basis below its carrying value for financial statement purposes and generating deferred taxes each reporting period. In connection with the adoption of APB 14-1, the Company recorded approximately $110,000 of deferred tax liabilities related to convertible securities interest to account for the future deferred tax impact of non-cash interest accretion. The Company's junior convertible trust preferred securities and 2008 senior convertible notes also generate deferred taxes because the Company's tax deductions are higher than the interest expense recorded for financial statement purposes.

        In March 2010, in connection with the closing of the investment in Artemis (discussed in Note 16 below), the Company recorded a deferred tax liability of approximately $67,000 for the tax effect of acquiring intangible assets that are not deductible for tax purposes in the United Kingdom.

At June 30, 2009,March 31, 2010, the Company has state net operating loss carryforwards that expire over a 15-year period beginning in 2009.2010. The Company also has foreign tax credit carryforwards that expire over a 10-year period beginning in 2010. The valuation allowances at December 31, 20082009 and June 30, 2009March 31, 2010 were principally related to the uncertainty of the realization of the foreign tax credits and the state net operating loss carryforwards, which realization depends upon the Company's generation of sufficient taxable income prior to their expiration.

        At June 30, 2009,March 31, 2010, the Company's liability for uncertain tax positions was $21,440,$22,249, including interest and related charges of $4,282.$4,165. The Company does not anticipate that this liability will change significantly over the next twelve months.

8.7. Earnings Per Share

        The calculation of basic earnings per share is based on the weighted average number of shares of the Company's common stock outstanding during the period. Diluted earnings per share is similar to basic earnings per share, but adjusts for the dilutive effect of the potential issuance of incremental shares of the Company's common stock. The following is a reconciliation of the numerator and

AFFILIATED MANAGERS GROUP, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

denominator used in the calculation of basic and diluted earnings per share available to common stockholders. Unlike all other dollar amounts in these Notes, the amounts in the numerator reconciliation are not presented in thousands.

        As more fully discussed in Notes 43 and 5,4, the Company had certain convertible securities outstanding during the periods presented and is required to apply the if-converted method to these

AFFILIATED MANAGERS GROUP, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

securities in its calculation of diluted earnings per share. Under the if-converted method, shares that are issuable upon conversion are deemed outstanding, regardless of whether the securities are contractually convertible into the Company's common stock at that time. For this calculation, the interest expense (net of tax) attributable to these dilutive securities is added back to Net Income (controlling interest) (reflectingreflecting the assumption that the securities have been converted).converted. Issuable shares for these securities and related interest expense are excluded from the calculation if an assumed conversion would be anti-dilutive to diluted earnings per share.

        The calculation of diluted earnings per share for the three and six months ended June 30,March 31, 2009 and 2010 excludes the potential exercise of options to purchase approximately 2.14.2 million and 1.3 million common shares, and the assumed conversion of the junior convertible trust preferred securities and the 2008 senior convertible notesrespectively, because the effect would be anti-dilutive.

        As discussed further in Note 18, the Company may settle portions of its Affiliate equity purchases in shares of its common stock. Because it is the Company's intent to settle these potential repurchases in cash, the calculation of diluted earnings per share excludes any potential dilutive effect from possible share settlements.

9.8. Commitments and Contingencies

        The Company and its Affiliates are subject to claims, legal proceedings and other contingencies in the ordinary course of their business activities. Each of these matters is subject to various uncertainties, and it is possible that some of these matters may be resolved in a manner unfavorable to the Company or its Affiliates. The Company and its Affiliates establish accruals for matters for which the outcome is probable and can be reasonably estimated. Management believes that any liability in excess of these accruals upon the ultimate resolution of these matters will not have a material adverse effect on the consolidated financial condition or results of operations of the Company.

AFFILIATED MANAGERS GROUP, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

        Certain Affiliates operate under regulatory authorities which require that they maintain minimum financial or capital requirements. Management is not aware of any violations of such financial requirements occurring during the period.

10. Affiliate9. Investments in Partnerships

        The activity in the Affiliate investments in consolidated partnerships was as follows for the three months ended March 31, 2010: