Two influential investor advisory groups recommended on Friday that Bank of America Corp shareholders vote to strip CEO Kenneth Lewis of his chairman role, adding to pressure on the bank's leader following the controversial buyout of Merrill Lynch & Co.

RiskMetrics Group and Glass Lewis & Co both recommended that shareholders vote against Lewis' re-election to the bank's board, amid questions over his handling of the Merrill deal.

Both advisory firms also said they support a shareholder proposal to enact a new policy to split the chairman and CEO role among different people at the bank, and they opposed the re-election of lead director O. Temple Sloan to the board.

Large investors often rely on these recommendations when casting their corporate ballots. Bank of America is holding its annual meeting on April 29, when the votes will be tabulated.

RiskMetrics also said it opposed the re-election of board members Jackie Ward, Frank Bramble, Monica Lozano and Robert Tillman, citing poor oversight of management.

Glass Lewis said it opposed the election of three former Merrill Lynch directors in addition to opposing the re-election of Lewis and Sloan to the board.

(Reporting by Martha Graybow, editing by Matthew Lewis)