Chris Dorfman, head of energy trading at Sempra Energy in London, has left the U.S. merchant energy outfit and is set to resurface at a London investment bank within the next few weeks, say market watchers. The oil trading veteran joined Sempra in the spring of last year to establish an oil trading presence in London. He was previously head of oil trading at Bank of America in London and prior to that was head of energy derivatives at Credit Lyonnais Rouse. An official at Sempra confirmed Dorfman's departure, but declined comment on where he is heading. Dorfman could not be reached for comment.