AMG Completes Investment in SouthernSun Asset Management

Affiliated Managers Group, Inc. (NYSE: AMG), today announced the completion of its investment in SouthernSun Asset Management, LLC (“SouthernSun”).

SouthernSun was founded in 1989 and manages long-term, concentrated portfolios through a fundamental, research-intensive investment process. The firm offers industry-leading U.S. small- and mid-cap strategies and a recently launched global investment strategy. As of December 31, 2013, SouthernSun’s U.S. institutional strategies rated in the top decile of their respective categories for the trailing three-, five- and ten-year periods, according to eVestment.

The firm’s flagship SouthernSun Small Cap Fund is rated five stars by Morningstar in the small blend category, and was named “Best Fund over Three Years” in the Small-Cap Core Funds category of the 2013 Lipper Fund Awards.

As part of the transaction, SouthernSun’s senior professionals have agreed to long-term commitments with the firm, and the SouthernSun funds have become part of AMG Funds, the Company’s U.S. retail distribution business. The terms of the transaction were not disclosed.

About Affiliated Managers Group

AMG is a global asset management company with equity investments in leading boutique investment management firms. AMG’s innovative partnership approach allows each Affiliate’s management team to own significant equity in their firm while maintaining operational autonomy. AMG’s strategy is to generate growth through the internal growth of existing Affiliates, as well as through investments in new Affiliates. In addition, AMG provides centralized assistance to its Affiliates in strategic matters, marketing, distribution, product development and operations. As of December 31, 2013, the aggregate assets under management of AMG’s Affiliates were approximately $568 billion (pro forma for pending investments), in more than 400 investment products across a broad range of investment styles, asset classes and distribution channels. For more information, please visit the Company’s website at www.amg.com.

Certain matters discussed in this press release may constitute forward-looking statements within the meaning of the federal securities laws. Actual results and the timing of certain events could differ materially from those projected in or contemplated by the forward-looking statements due to a number of factors, including changes in the securities or financial markets or in general economic conditions, the availability of equity and debt financing, competition for acquisitions of interests in investment management firms, the ability to close pending investments, the investment performance of our Affiliates and their ability to effectively market their investment strategies, and other risks detailed from time to time in AMG’s filings with the SEC. Reference is hereby made to the “Risk Factors” set forth in AMG’s Form 10-K for the year ended December 31, 2013.

AMG routinely posts information that may be significant for investors in the Investor Information section of its website, and encourages investors to consult that section regularly. For additional information, please visit www.amg.com.