Jeffrey Greenberg, who in June resigned from American International Group, the global insurer run by his father M.R. Greenberg, is the newest partner of the investment banking subsidiary of Marsh & McLennan Cos.

Robert Clements, chairman of Marsh & McLennan Risk Capital Corp., announced the appointment Thursday.The move is a homecoming of sorts for Mr. Greenberg. He began his insurance career with Marsh & McLennan's insurance brokerage unit in 1976 and was head of a group specializing in commercial aviation and aerospace in New York.

"Jeff is one of the most respected figures in the insurance industry," Mr. Clements said in a statement. "He will be an invaluable asset in helping us make the right investments and applying his management experience and expertise to the companies in which we invest."

Mr. Greenberg, 44, most recently headed AIG's domestic brokerage group. He resigned in June after 17 years with the insurance company less than two weeks after his younger brother, Evan Greenberg, was promoted to executive vice president, the same corporate level as Jeffrey Greenberg.

Mr. Clements said Jeffrey Greenberg will be involved in a broad spectrum of activities at the Greenwich, Conn.-based firm. The company is investment adviser to the Trident Partnership LP, one of the largest dedicated insurance industry equity funds, and to Risk Capital Reinsurance Co., a newly formed reinsurer.

In a statement, Mr. Greenberg said he has "great respect for the company and its people and feel it is well positioned to seize the opportunities presented by industry consolidation."