Affiliated Managers Group Inc. (AMG), a global asset management company, is acquiring an asset management firm and an interest in an alternative investment firm, the companies announced today.

AMG has agreed to acquire River Road Asset Management LLC, based in Louisville, Ken., from Aviva Investors North America Holdings Inc.

Terms of the two deals were not revealed.

River Road has about $11 billion in AUM. It invests for low-volatility over a long term and has 16 investment professionals who serve an institutional and retail client base.

River Road has a longstanding relationship with a part of the AMG Funds business, Aston Asset Management LP, and will continue to serve as sub-advisor for six mutual funds in the Aston Funds family, according to the firms. River Road's management team will continue to own a substantial portion of the equity and will direct the firm's day-to-day operations.

AMG also is acquiring an equity interest in EIG Global Energy Partners LLC (EIG). EIG’s management team will continue to hold a majority of the equity in the company and will retain operating autonomy of the business.

EIG, based in Washington D.C., is a global alternative investment firm specializing in private investments in energy and energy-related infrastructure.

EIG also announced that William C. Sonneborn has been appointed president of EIG effective in May. Sonneborn currently serves as senior advisor to Kohlberg Kravis Roberts & Co. and as a member of KKR's management committee.