Alex Reyfman, U.S. credit derivatives strategist at Goldman Sachs in New York, is joining Bear Stearns. Reyfman, who could not be reached, is thought to be joining the firm in a similar role, according to an official familiar with the move. Bruce Corwin, spokesman at Goldman in New York, confirmed his departure and declined further comment. Michele Agostinho, spokeswoman at Bear Stearns in New York, declined comment.