Global Payments didn’t disclose what type of data had been accessed, but said it had notified “appropriate industry parties to allow them to minimize potential cardholder impact.”

News of the breach broke in the morning but Global Payments confirmed it only after the market close. Global Payments shares tumbled 9% to $47.50 a share on the New York Stock Exchange, after people involved in investigating the breach identified the company to The Wall Street Journal as the victim of the attack. The stock was halted at midday. The company is scheduled to report quarterly earnings on April 4.

The breach underscores the mazelike network of the U.S. payment system, where little-known companies play important roles in processing billions of transactions each day. Global Payments is part of a group of companies called “third-party processors,” that serve as middlemen between merchants and banks.

Global Payments was the seventh-largest “merchant acquirer” in the U.S. last year, according to the Nilson Report, a payments-industry newsletter. Merchant acquirers have contracts with retailers to handle the processing of card transactions, including debit cards, credit cards and gift cards. Such third-party processors have been the target of big hacker attacks in the past.

via Breach Hits Card Processor Global Payments –