US authorities have charged 11 people in connection with the theft of the credit and debit card details of about 40 million people.
The US Department of Justice believes it is the largest identity theft case it has ever prosecuted.
The stolen numbers were sold via the Internet to other criminals in the US and Eastern Europe, and used to withdraw tens of thousands of dollars at a time from ATMs.
The group allegedly hacked into shop and bank computer systems, installing software to gain access to the data.
Three of those charged are US citizens. The others come from Estonia, Ukraine, Belarus and China.
