Mr Lewis was voted out as chairman back in April

Bank of America's beleaguered chief executive Kenneth Lewis is to retire at the end of the year.

The announcement comes after Mr Lewis has faced continuing criticism over his running of the firm, particularly last year's decision to buy Merrill Lynch.

This $50bn (£31bn) deal depleted Bank of America's cash reserves, and it subsequently needed a government bail-out as the financial crisis worsened.

Shareholder had already ousted Mr Lewis, 62, as chairman in April.

Analysts said at the time that Mr Lewis would not be able to continue much longer in the chief executive position.

'Overly targeted'

Mr Lewis had led the company since 2001.

"It's a good thing for the company to make a clean break and move forward," said analyst Walter Todd of Greenwood Capital.

"Ken Lewis has been overly targeted in terms of how things played out. But the fact is, perception is reality in these situations, and the perception is, everything that happened with the Merrill transaction was his fault."

Bank of America, which has needed $45bn of state support, said it was looking at potential successors.

Mr Lewis has also been criticised over Bank of America's decision to authorise $5.8bn (£3.4bn) of 2008 bonuses to senior Merrill employees, despite the investment bank making a loss of $27.6bn last year.

The US financial regulator, the Securities & Exchange Commission (SEC), said earlier this month that it will sue Bank of America over charges that it misled investors over the bonuses.

Bank of America said it would "vigorously defend" itself in court.