US Federal Reserve Ben Bernanke has been accused of using bullying tactics against executives of America's biggest bank.
The Bank of America bought Merrill Lynch last year during the height of the financial crisis and suffered severe losses.
Mr Bernanke has denied accusations the Fed threatened Bank of America executives if they halted a merger with Merrill Lynch or pressured them to withhold bad news about the troubled investment bank.
"Neither I nor any member of the Federal Reserve ever directed, instructed, or advised Bank of America to withhold from public disclosure any information relating to Merrill Lynch," Bernanke told the House of Representatives committee.
The top Republican on the panel, Representative Darrell Issa, on Wednesday charged the Fed had covered up its involvement in the merger and "deliberately hid" important details from other federal regulators.
White House spokesman Robert Gibbs said on Thursday that President Barack Obama had confidence in the job Mr Bernanke has done so far, despite congressional criticism over his role in the Bank of America merger with Merrill Lynch.