Tina Leung, a managing director and bank loan sourcer at Bear Stearns, has left the firm. The reasons for her departure could not be determined, though Bear Stearns officials confirmed her move. Leung could not be reached. Prior to joining Bear Stearns, Leung worked at Donaldson, Lufkin & Jenrette. A Bear Stearns spokeswoman did not return calls.