Citigroup Inc. is being reviewed by the Office of the Comptroller of the Currency for apparently being in violation of fair lending standards, according to a report by Reuters.

The company learned — and self-reported to the OCC — that discounts available under a program offering lower mortgage rates were being extended to wealthy borrowers having a certain amount of deposits or wealth with the bank but not to certain minority customers, unidentified sources told the news agency. At the time, Citi informed the OCC that that inconsistency was inadvertent.

The OCC is investigating the matter, according to the news outlet. The company may be levied a fine or placed under more stringent supervision by the OCC, among other things, if the regulator finds wrongdoing.

A Citi representative, while acknowledging that the problems existed, told Reuters that the company believes that it did not violate fair lending regulations.