Harvey Golub, a respected former head of American Express, has emerged as the frontrunner to become chairman of AIG, in a move that would provide the stricken insurer with a robust defender against congressional critics.

Mr Golub, who joined AIG’s board in June, has the edge over other candidates, including ­Dennis Dammerman, the former General Electric executive who is also a director of the government-controlled insurer, people close to the situation said.