James Rosenthal, Morgan Stanley’s chief operating officer, is retiring, according to a memo reviewed by The Wall Street Journal.

Rosenthal will stay on as a senior adviser, according to the memo, whose contents were confirmed by a firm spokesman. He joined the firm in 2008 and was its strategy chief in 2011, when he was named COO. In that role, he has helped manage the day-to-day operations of the firm under chief executive James Gorman.