American Express is facing a $350 million fine from the Treasury Department's Office of the the Comptroller of the Currency for failing to comply with federal bank secrecy and anti-money laundering rules.

Deficiencies included "involved inadequate resources, including staff without sufficient expertise, systemic internal control gaps, weak independent testing," and other shortcomings, the OCC said.

The regulator issued a cease and desist order in an action that was coordinated with the Federal Reserve. American Express's failures to maintain adequate processes resulted in "the bank's failures to timely identify and report significant missed suspicious activity and to provide important information to law enforcement," Comptroller of the Currency Jonathan Gould said.

American Express didn't immediately respond to a request for comment. The stock was down 1.3% in after-hours trading.

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