CHARLOTTE, N.C. -- Ken Lewis has lost his role as Bank of America's chairman, and now he'll have to prove to shareholders that he should keep his post as the troubled bank's CEO.

After months of rancor following Bank of America's acquisition of troubled investment bank Merrill Lynch, shareholders voted at the company's annual meeting to separate the jobs of chairman and CEO. Lewis will remain the CEO of the bank, while board member Walter Massey, president emeritus of Morehouse College in Atlanta, will become Bank of America chairman.

Some analysts believe Lewis might eventually be forced out altogether.

Gary Townsend, chief executive officer of Hill-Townsend Capital, noted that Wachovia Corp.'s chairman and CEO roles were split last year after shareholders were upset about the performance of that bank, which has since been sold to Wells Fargo.

Then, just weeks after Wachovia CEO Ken Thompson lost his title as chairman, he was ousted as chief executive as well. Stripping Lewis of his role as chairman "can result in significant, rapid changes, depending on what happens the rest of the year," Townsend said.

Lewis' star began to fall soon after the deal to buy Merrill Lynch was completed Jan. 1, as Merrill reported $15 billion in fourth-quarter losses and it was learned that Bank of America had approved the early payout of billions of dollars in bonuses to Merrill employees.

Lewis, 62, who served as chairman and CEO since 2001, has spent much of this year defending his actions — and did so again during the angry four-hour shareholders' meeting.

Big investors including California's employee pension fund had called for shareholders to oust Lewis and his fellow directors at the meeting, which was attended by more than 2,000 people. But shareholders did vote to retain the entire board.