Feb. 23 (UPI) -- Citigroup announced Friday it is refunding $335 million to nearly 2 million credit cards after determining the company improperly calculated annual interest rates.
The credit card company said it discovered the error during a routine internal review and reported it in a filing to the Securities and Exchange Commission.
"We sincerely apologize to our customers and are taking every action to provide refunds as quickly as possible," bank spokeswoman Elizabeth Fogarty said in a statement.
The error happened in the way Citigroup recalculated interest rates for customers who had incurred penalty rates for late payments. Credit card companies are required to adjust the interest rates after those customers resume paying on time.
The "methodological issues" date back to 2011, and affected customers are entitled to a $190 refund on average.
"While we have found no evidence of employee misconduct, we should have identified these issues sooner," the bank said. "We sincerely apologise to our customers and are taking every action to provide refunds as quickly as possible."