The Federal Reserve said some of the largest US banks are stumbling in efforts to assess their own potential risks and financing needs, raising the possibility that banks could be pushed to increase their capital or curtail dividends and share buybacks to satisfy regulators.

Most large banks have made progress in evaluating and preparing themselves to withstand a severe economic downturn, the Fed said in a study released Monday. But it said there is "still considerable room for advancement" in the so-called stress tests run by some individual firms.