AIB has lost personal information of around 550 of its customers in the West of Ireland.
The printed spreadsheets containing confidential customer details were mislaid by a staff member in Galway on the 31st August.
AIB says it's contacted all those affected. In a letter to a customer obtained by RTEÌ Raidio na Gaeltachta, the banks says that the information included names, loan and deposit balances, as well as account turnover and annual fees.
AIB is reassuring customers that their funds can't be accessed because there were no contact details included.
In a statement, AIB says that it takes its Data Protection Obligations very seriously and that its apologised unreservedly to those affected.
It added that the incident has been reported to the Office of the Data Protection Commissioner.
Kim Buckley has this report:
