US regulators rejected Wednesday the bankruptcy contingency plans of five giant US banks that aim to avoid taxpayer bailouts if they fail.

Both the Federal Reserve and the Federal Deposit Insurance Corporation said the "living will" plans were "not credible" for Bank of America, Bank of New York Mellon, JPMorgan Chase, State Street and Wells Fargo.

The five "too big to fail" banks were given until October 1 to improve the plans, which were required in the Dodd-Frank regulations governing systemically important banks in the wake of the devastating 2008 financial crisis.

Failure to pass the test could result in higher capital requirements and other toughened standards, such as restrictions on bank operations.

The regulators found that the living wills of two other large banks, Goldman Sachs and Morgan Stanley, also had weaknesses. They were ordered to address the deficiencies, but did not technically fail the test.

The FDIC found that Goldman's plans "was not credible or would not facilitate and orderly resolution under bankruptcy," the FDIC said. The Federal Reserve came to that same conclusion about Morgan Stanley.

Regulators also found problems in Citigroup's plan but "they did not believe the shortcomings rose to the level of the statutory required for a joint determination of non-credibility," the FDIC said.