Two members of UBS AG's Wealth Management Americas' executive committee have stepped down, while Robert McCann, the Swiss bank's most senior executive in the United States, is among six officials whose titles have changed from chief executive to president.

John J. Brown, 56, who ran the middle-market banking unit that sells investment banking services to wealth management clients for their businesses, retired this week, a UBS spokesman said on Wednesday.

Brown joined UBS in 2009, soon after McCann took the helm of the then money-losing brokerage business formerly known as PaineWebber.

Dan Cochran, 68, who joined in 2010 to coordinate McCann's duties in the United States with his responsibilities in Zurich, retired as chief of staff at the end of February, the spokesman said.

The executives' departures have not been announced externally, but their names no longer appear on UBS Wealth Management's executive committee web page.

Brown's responsibilities have migrated to Paul Hatch, who runs the UBS Wealth Americas' "advice and solutions" unit that develops products sold by the bank's approximately 7,000 brokers. Cochran's functions have been absorbed by Kathleen Lynch, chief operating officer of UBS Group Americas and UBS Wealth Management Americas.

McCann is one of six members of UBS AG's Group Executive Board - he also runs UBS Group Americas - whose titles changed to president from chief executive in recent weeks. Their roles haven't changed, but the new titles clarify what they do, the spokesman said.

Like many senior managers at UBS Wealth Americas, McCann, Brown and Cochran were long-time Merrill Lynch executives who joined after Bank of America Corp bought Merrill during the 2007-2009 financial crisis.

Since McCann's arrival in October 2009, he has restored UBS Wealth Management Americas to profitability by focusing on clients with more than $10 million and by selling them mortgages, loans, and other bank products and services.