Credit Firms Drop Card Processor

BOSTON — Visa USA Inc. and American Express Co. are cutting ties with the payment-processing company that left 40 million credit and debit card accounts vulnerable to hackers in one of the biggest breaches of consumer data security.

CardSystems Solutions Inc. “has not corrected, and cannot at this point correct, the failure to provide proper data security for Visa accounts,” said Rosetta Jones, a spokeswoman for Foster City-based Visa.

She said banks that issue Visa cards would have until Oct. 31 to replace CardSystems with one of the hundreds of other payment- processing companies in the U.S.

American Express also notified CardSystems it would sever their relationship as of October, spokeswoman Judy Tenzer said. CardSystems was a small part of American Express’ network, handling less than 0.5 percent of its transactions, she said.

CardSystems released a statement saying it was “disappointed and very surprised,” and hoped Visa would reconsider. The company did not address American Express’ decision.