UK credit broker loans.co.uk has written to thousands of customers informing them of a potential security breach.
Loans.co.uk says it recently found out that some customer information has been provided to rival loan companies without authorisation.
The theft of names, addresses, phone numbers and financial details affects people who have applied for a loan, says the firm in a statement, but does not appear to have troubled exisiting customers.
Affected individuals claim to have been inundated with junk mail and pushy phone calls from shady credit card outfits.
The lender says it has no reason to believe the information has been used for anything other than marketing purposes. Nonetheless it is offering all the target names one year's free subscription to a credit monitoring service.
The firm has called in police and informed the Information Commissioner's Office about the breach. It has also written to all potential victims to warn of the risks and is offering one year's free subscription to CreditExpert, a credit monitoring service.