Citigroup Inc. said on Friday that it had failed to properly reduce interest charges on some 1.75 million credit card accounts since 2011, prompting a $335 million refund to customers later this year, Reuters reported. The refund, which will average $190 per account, stems from the bank’s discovery that it had not used a proper method for reducing interest charges for cardholders who resumed timely payments after having had to pay penalty rates for lapses. The errors amounted to about 10 percent of the interest reductions cardholders were due, the bank said. It estimated that the other 90 percent of rate savings were properly credited to accounts.
