Greg Fleming, co-president of Merrill Lynch and head of its investment banking unit, has offered his resignation to the firm, sources told CNBC, only days after Merrill completed its merger with Bank of America.
The development follows the departure, announced earlier this week, that Merrill's brokerage head, Bob McCann, would leave the company.
The departure of Fleming, like that of McCann, has less to do with any cultural rift with Bank of America than with ongoing tensions with John Thain, Merrill's chief executive and president of Bank of America's global banking.
Thain, a former Goldman Sachs executive, joined Merrill in 2007.
The loss of Fleming, like that of McCann, could be devastating for Merrill, as both men have wide followings within the firm's workforce.