Shareholders at an annual meeting voted narrowly to split Lewis's jobs, The Wall Street Journal reported Wednesday.
Lewis will keep his CEO and president responsibilities.
After the vote, the board elected bank Director Walter Massey to serve as chairman.
Executives from Habitat for Humanity and the United Way pitched support for Lewis, who has been criticized for the bank's purchases of Merrill Lynch and Countrywide Financial Corp.
Shareholders have expressed disapproval over the secrecy of the Merrill Lynch deal. Lewis has said former Treasury Secretary Henry Paulson Jr. and Federal Reserve Chairman Ben Bernanke urged him to remain quiet about details of the transaction, fearing a derailed deal would ripple through the financial system.
In its fourth-quarter report, the bank revealed Merrill Lynch's losses for the quarter were more than $15 billion. It also said it had accepted an additional $20 billion in government assistance, bringing its government bailout total to $45 billion, the Charlotte, N.C., Business Journal said.
Bank of America's share values, which have dropped 76 percent since January, fell 9 percent Tuesday on reports that Treasury would mandate the bank increase its capital reserves.