John Thain, who engineered Merrill Lynch & Co. Inc.'s sale to Bank of America Corp., was ousted after Merrill's $15.4 billion loss forced its parent to seek more money from the federal government.
Mr. Thain "agreed his situation was not working out, and that he should resign," Robert Stickler, a B of A spokesman, said in an e-mail Thursday.
The executive's tenure with B of A ended less than a month after Merrill's takeover was completed.
He negotiated the sale with Kenneth Lewis, B of A's chief executive, but Mr. Thain's credibility was undercut when the brokerage reported a record fourth-quarter deficit.
Mr. Lewis, who considered backing out of the deal when he learned of the extent of Merrill's losses last month, went ahead at the insistence of federal regulators, who provided a new $138 billion aid package.
Tom Montag, the trading chief hired by Mr. Thain from Goldman Sachs Group Inc., will stay with B of A, according to Mr. Stickler.