US bank JPMorgan Chase says computer tapes containing the personal financial information of 2.6 million current and former credit card customers were mistakenly identified as rubbish and thrown out.
The bank says it notifying 2.6 million former and current holders of Circuit City-branded credit cards of the incident and is monitoring all affected accounts.
In a statement, Rich Srednicki, chief executive officer of Chase Card Services, which issues the credit cards for consumer electronics retailer Circuit City, says: "We take responsibility for this and are making every effort to let affected cardmembers know what we are doing and what we suggest they do to protect themselves."
After an investigation by federal and local authorities, Chase says it believes the tapes - which were stored in a locked box and contained some card holders' social security numbers - were buried at a landfill site.
Chase says it has not identified any misuse of personal information but it is offering a one-year free credit monitoring service to those card holders whose social security numbers were on the tapes.
The bank says account holders will not be liable for unauthorised transactions.
Last month the UK's Information Commissioner's Office said it was investigating claims that high street bank NatWest, which is owned by the Royal Bank of Scotland, allegedly dumped customers' confidential financial details in an outside rubbish bin.