Ten of America's largest 19 banks need a combined $74.6bn (£50bn) of extra funds to boost their cash reserves, BBC reported.
That is the main finding of the so-called "stress tests" to see if the banks have sufficient capital to cope should the recession worsen.
Bank of America is the most at risk, needing an additional $33.9bn.
"Our hope with today's actions is that banks are going to be able to get back to the business of banking," said US Treasury Secretary Timothy Geithner.
Other banks that need more money include Wells Fargo, which is said to require $13.7bn, and GMAC, the financial arm of General Motors, which needs $11.5bn.
Citigroup requires an additional $5.5bn of funds, and Morgan Stanley has been told to find $1.8bn.
The 19 banks that were tested by Treasury Department and Federal Reserve officials account for two-thirds of the total assets of the US banking system, and more than half of the total amount of credit in the US economy.
Mr Geithner said earlier on Thursday that no US bank being screened by regulators was at risk of insolvency, comments echoed by Federal Reserve Chairman Ben Bernanke.
The treasury secretary said he believed that the majority of the banks would be able to raise any additional money they need from private sources, but if they were unable to do so the government may have to provide them with more taxpayer money.
Analysts broadly welcomed the results of the stress tests.
"It seems to be that the leaks were very accurate, so there doesn't seem to be any major surprises," said Eric Kuby of North Star Investment Management.
"The fears of nationalisation or of failure have more or less disappeared."
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