New York Life Insurance Company said Thursday that it has agreed to buy a minority stake in Minneapolis-based Cornerstone Capital Management, Inc.—and under the terms of the deal, the firm will gradually increase its ownership in the Minnesota company.

New York Life said that it will acquire the minority stake through its mutual fund distribution subsidiary, MainStay Investments. (According to a report by the Star Tribune, New York Life plans to acquire a one-third interest in the firm.) Financial terms of the deal were not disclosed, but the agreement calls for New York Life to increase its ownership—over a period of seven years—to a majority stake.

Cornerstone Capital Management was founded in 1992, and the investment and financial advisory firm now has more than $2.2 billion in assets under management. It manages the Keystone Large Cap Growth Fund, which invests primarily in U.S. companies, focusing on common stocks of “high-growth, large-capitalization companies” with at least $3 billion in market capitalization, according to New York Life.

Under the terms of the deal, the Keystone Large Cap Growth Fund, which had $330 million in assets as of July 31, will be integrated into New York Life’s funds and be called the “MainStay Cornerstone Growth Fund,” pending shareholder approval. The firms expect the deal to close around January 13.

“Partnering with one of America’s strongest and most well-regarded financial institutions is part of our strategic growth plan and provides increased opportunities for our clients and our team,” Cornerstone Capital Management CEO Andrew Wyatt said in a statement. “This partnership enables Cornerstone to preserve its long-standing investment and management philosophies and continue its focus on performance while benefiting from New York Life’s global breadth and depth in distribution, marketing, and service.”

Yie-Hsin Hung, senior managing director and head of institutional investments for New York Life’s investment group, said in a statement that Cornerstone Capital Management has “a strong track record of achieving long-term investment success for its clients,” and its “expertise in investing in large-cap growth equities complements our overall investment capabilities and positions us for growth.”

As of July 31, Mainstay Investments had more than $63.5 billion in assets under management, and New York Life’s larger investment group managed more than $345 billion.