MasterCard and Visa said Friday that they had notified issuers of its credit cards of a potential breach of the security of customer accounts. The companies did not say how many customers were affected. Global Payments Inc., which processes credit card transactions for stores, said it had detected a breach of card data in early March. Breaches of card data can lead to identity theft and unauthorized charges. Global Payments said it had alerted federal law enforcement and was investigating. Spokeswoman Amy Corn would not say whether cards besides Visa and MasterCard were affected. Global Payments stock was halted after published reports said it was responsible. The stock fell 9 per cent for the day before trading was stopped. Credit card companies generally protect customers against fraudulent transactions, and Visa said specifically Friday that its U.S. customers were not at risk. Both Visa and MasterCard said their own systems had not been compromised. Last June, hackers stole information for 360,000 credit card accounts at Citigroup. In the past year, there have been high-profile data attacks against the International Monetary Fund, National Public Radio, Google and Sony's PlayStation Network.
