Bank of America, based in Charlotte, N.C., and Merrill Lynch agreed to the $50 billion sale in September, a move that would make the largest depository bank in the country even more formidable.

With consolidated assets of $1.8 trillion, Bank of America is "the largest depository organization in the United States," the Fed said Wednesday.

Measured by deposits, BOA controls approximately $774.2 billion, "approximately 10.8 percent of the total amount of deposits," in U.S. insured accounts, the Fed said.

Merrill Lynch assets total $875 billion with deposits around $77.8 billion, the Fed statement said.

However, the Fed said, the deal, also reviewed by the U.S. Department of Justice, "would not likely have a significantly adverse effect on competition in any relevant banking market or in any relevant market."