Merrill Lynch made changes in its mortgage unit.

Merrill Lynch took the actions in a shake-up of the mortgage securities unit that racked up trading losses of $250 million in recent weeks. Robert Andres, president of Merrill Lynch Mortgage Capital, and Bowers Espy, executive vice president, were relieved of trading responsibilities. Gregory Herschell, a vice president in the unit, was suspended from his regular duties and not reassigned, the firm said. Howard Rubin, a senior trader, was fired last week as the company disclosed losses that were linked in part to unauthorized trading, as bond prices fell sharply in recent weeks.