A Republican congressman on Wednesday accused the Federal Reserve of a “cover-up” over the Bank of America-Merrill Lynch takeover, raising the stakes ahead of Fed chairman Ben Bernanke’s appearance on Thursday before a House subcommittee investigating the deal.

Darrell Issa, the senior Republican on the subcommittee, said the Fed “engaged in a cover-up and deliberately hid concerns and pertinent details regarding the merger from other federal regulatory agencies”.