The hotel chain Marriott admitted on Tuesday that backup computer tapes containing data on approximately 206,000 customers were missing from a company office in Florida.
The data, which relates to customers of its timeshare division, Marriott Vacation Club International (MVCI), included personal information such as the credit card details, social security numbers and, in a few cases, the bank details of customers.
The company said it has contacted the affected customers and is offering to enroll them free-of-charge in a credit monitoring service, so that customers can discover if there is any irregular activity on their account.
"We regret this situation has occurred and realize this may cause concern for our associates and customers," said Stephen Weisz, the president of MVCI.
The company has launched an investigation into how the tapes went missing.
Customers of MVCI who are concerned they may have been impacted can find out more information from the company Web site.