Affiliated Managers Group has reached a definitive agreement with Russell Investments, a subsidiary of Northwestern Mutual Life Insurance Company, to acquire Pantheon Ventures, the private equity fund of funds manager and subsidiary of Russell Investments.

Under the terms of the purchase agreement AMG will pay around $775 million in cash with the potential for additional payments over the next five years, contingent on the growth of Pantheon’s business, the firm said in a press statement.

The transaction will be funded with a combination of AMG’s available cash and existing credit facility, and is expected to close during the second quarter of this year subject to closing conditions and regulatory approvals.

Meanwhile the management at Pantheon – which manages approximately $22 billion for clients through offices located in London, San Francisco, New York and Hong Kong – will continue to direct the company’s daily operations and retain a stake in the partnership, with 21 management partners entering into long-term employment agreements with AMG.

Last December AMG also announced plans to acquire a majority stake in Aston Asset Management via the purchase of Highbury Financial, Aston’s parent firm.