US retailer Target is being sued by at least 11 customers over a credit card security breach that saw details of more than 40 million cards stolen.
The lawsuits, each seeking class-action status, were filed in US courts in recent days and seen by the BBC. Meanwhile, major US banks have moved to limit damages by restricting spending on debit cards.
Security researchers said the stolen card numbers had been seen on underground markets.
US Senator Chuck Schumer has called for the Consumer Financial Protection Bureau to investigate the breach.
Target told the BBC it does not comment on pending litigation.
The thieves managed to grab key details for so many cards by getting malware on to the computer systems at the checkout desks in almost 1,800 Target stores in the US.