JP Morgan Chase and Bank of America are among several US banks under investigation for breaches that may have let money flow to terrorists or drug dealers, according to The New York Times.
Officials told the newspaper they had launched one of the most aggressive crackdowns on money laundering in decades.
Federal and state authorities are looking into the banks for their failure to monitor cash transactions through their branches that could have allowed the criminals to engage in money laundering, the paper reported on Saturday, citing several anonymous sources.
Although the probe is not yet complete, regulators are close to taking action against JPMorgan, including a possible cease-and-desist order that would require the bank to fix any gaps in oversight, the Times said.
Investigators are also looking into the activities of Bank of America and other Wall Street giants.
JPMorgan was already in regulators' crosshairs in 2011, accused of having violated US economic sanctions against Cuba and Iran.
US authorities have recently blacklisted several large European banks and their US subsidiaries for illegally trading with the sanction-hit countries.
British bank Standard Chartered, accused of having conducted illegal transactions with Iran, was forced to pay a $340 million fine in mid-August to avoid a Wall Street ban.
And the US Federal Reserve and the Justice Department are also investigating the Royal Bank of Scotland for possible violations of the US sanctions against Iran, the Times previously reported.