Citi Cards Japan Inc. says personal information about some 92,400 customers, including names, addresses and credit card numbers, may have been leaked, but no unauthorized use of the cards has been reported.
A person involved in a company to which Citi Cards outsourced part of its business illicitly obtained the information and sold it to a third party, the unit of Citigroup said Friday.
The case has been reported to the police, it said.
Citi Cards said unauthorized use of the cards is unlikely because security codes, such as personal identification numbers, weren’t included in the leaked information.
Customers will be exempt from paying bills resulting from unauthorized use of the cards, it said.
The incident came to light last month after a cardholder reported that he had noticed that his information had been leaked.