Patrick Mortimer, head of Morgan Stanley's (MS.N: Quote, Profile, Research, Stock Buzz) U.S. prime brokerage business, resigned this week amid declining assets and profits of hedge fund clients that make up the division's client base, the Wall Street Journal said, citing people familiar with the matter.

Mortimer, a 20-year veteran of the firm, left for personal reasons and does not appear to have been pushed out, the paper said, citing the people.

Stuart Hendel, global head of the prime brokerage unit, and other executives will assume Mortimer's duties, the people told the paper, adding that no direct replacement for Mortimer is planned.

Reuters efforts to contact Morgan Stanley out of regular office hours were unsuccessful, while a spokesman from the company's office in Hong Kong was not immediately available to comment.

(Reporting by Ajay Kamalakaran in Bangalore; Editing by Lincoln Feast)

Investment Morgan Stanley Citigroup