James McDonald, president and chief executive of multifamily office Rockefeller & Co. and a member of the New York Stock Exchange's board of directors, died on Sunday in an apparent suicide, media reports said.

Mr McDonald was found shot to death in his car at about 3 pm on Sunday in Dartmouth, Massachusetts., according to the Associated Press. The vehicle was parked behind an automobile dealership.

A spokesman for the Bristol district attorney's office in Massachusetts today told the news service that 56-year-old Mr McDonald appeared to have shot himself, but that the matter was still under investigation.

Dartmouth is a town of about 30,000 residents near New Bedford, Massachusetts, and about 25 miles south of Boston. Mr McDonald lived in Manhattan.

He joined Rockefeller from Pell Rudman Trust - now Invesco's Atlantic Trust - in 2001. In 2008,  SG Private Banking, the wealth-management division of Paris-based Société Générale, took a 37 per cent stake in Rockefeller Financial Services, the parent company of Rockefeller & Co.

In May 2009, Mr McDonald retired from the board of board of CIT Group. He was also on the board of NYSE Euronext.

Rockefeller & Co.'s chief operating and financial officer Austin Shapard has temporarily taken leadership of the firm, according to spokesman Joseph Kuo.

Rockefeller & Co. is the successor to the John D. Rockefeller family office, which was founded in 1882 and became a commercial multifamily office about 100 years later. Though it caters to some institutional clients, its mainstay is providing wealth and investment-management services to families with more than $30 million in investable assets.

Rockefeller & Co. had $25 billion under administration at the end of June 2009. It has offices in Boston and Washington, D.C., in addition to its headquarters in New York.