Boston-based global asset manager Affiliated Managers Group (AMG) has acquired a majority shareholding in investment manager Trilogy Global Advisors.

Trilogy specialises in emerging and global market strategies and had about US$12 billion in assets under management at June 30, 2010.

"The addition of Trilogy extends our position in outstanding global and emerging markets products, which will account for nearly 40 per cent of our earnings upon the closing of the transaction," AMG president and chief executive Sean Healey said.

"We are confident in Trilogy's outstanding long-term growth prospects. Global and emerging markets are among the fastest-growing areas in the asset management industry and Trilogy is a leader among firms investing in these areas."

The management partners of Trilogy will continue to hold a substantial portion of the equity of the business and direct its day-to-day operations.

Trilogy has 21 investment professionals. All members of the management team will remain with the firm and all of the firm's senior partners have entered into long-term employment agreements with the firm and AMG.

"We are now in a position to facilitate succession planning through a structure that ensures a robust incentive plan is in place for the next generation," Trilogy chief investment officer and co-founder William Sterling said.

AMG, which has an office in Sydney, buys stakes in small to mid-sized asset managers, but lets the managers remain autonomous.

In turn, the managers agree to share revenues and a designated portion of revenue is allocated to expenses, the affiliate's management team and AMG.