Payment processor Global Payments today confirmed that up to 1.5 million credit card numbers may have been stolen in the security breach that was reported on Friday. Global Payments identified and reported unauthorized access into a part of its processing system in early March. The forensic investigation revealed that “Track 2” (account number, expiry date) data from all major card brands may have been accessed but not cardholder names and addresses. The stolen data could be used to counterfeit new cards.

Global Payments is one of the largest merchant acquirer in the U.S., handling 2.44 billion purchase transactions last year alone. The Atlanta-based company enables merchants to accept credit and debit card payments. Companies in the payment-processing chain are often attacked by hackers because they handle a large amount of sensitive financial information. For this reason credit companies emphasize advanced security through EMV chip technology to minimize the impact of data compromises. Visa has already issued more than one million Visa EMV chip-enabled credit cards in the U.S.