HONG KONG—Citigroup Inc. said hackers have viewed some of its credit-card customers’ account information in North America.
The company said roughly 1% of customers’ accounts were viewed but didn’t estimate the actual number affected. Citi Cards is one of the industry’s largest providers of credit cards with more than 21 million accounts generating more than $77 billion in receivables in North America according to its 2010 annual report.
“During routine monitoring, we recently discovered unauthorized access to Citi’s Account Online,” it said in an emailed statement. A spokesman said Citi’s debit cards weren’t affected.
The New York-headquartered bank said that hackers didn’t gain access to customers’ Social Security numbers, dates of birth, card expiration dates or card security codes.
Citi is contacting customers whose information was viewed and has implemented procedures to prevent a recurrence of this type of event.