Troubled assets are still plaguing the U.S. financial system, and a recent report from the Congressional Oversight Panel concluded some smaller banks may need additional $12 billion to $14 billion in funds from the Troubled Asset Relief Program (TARP) and may need a stress test of their own.

According to data compiled by Bloomberg News, more than 150 publicly traded U.S. banks have nonperforming loans that account for 5% or more of their total assets. Almost 300 banks showed troubled assets accounted for 3% or more of their holdings.

Some smaller, lesser-known banks, like Michigan-based Flagstar Bancorp Inc. (NYSE: ), which said in its second-quarter filing with the Securities and Exchange Commission it was considered to be “well capitalized” and are not subject to regulatory capital requirements actually have troubled assets that exceed 10%, Bloomberg said.

'At a 3% level, I’d be concerned that there’s some underlying issue, and if they’re at 5%, chances are regulators have them classified as being in unsafe and unsound condition,” Walter Mix, former commissioner of the California Department of Financial Institutions and now a managing director at consulting firm LECG Corp. (Nasdaq: ) told Bloomberg.

Three lenders with nonaccruing ratios of 6.2% as of March closed earlier this month: Corus Bankshares Inc. (Nasdaq: ), Guaranty Financial Group Inc. (NYSE: ) and Colonial BancGroup Inc.