Banking giant HSBC says a computer server holding the confidential personal details of around 159,000 customers has gone missing from a branch in Hong Kong.
The server - which contains account numbers, customer names and transaction details - disappeared on 26 April during renovation work at a Kwun Tong branch in east Kowloon on April 2.
In a statement, the bank says the server does not contain any customer PINs, passwords or user IDs and has "multiple layers of security".
Vincent Cheng, chairman, China and Asia operations, HSBC, told reporters that affected customers would not be liable for any losses arising from the situation.
But local media reports say angry customers have been flocking to the Kwun Tong branch to complain about the data breach, with some people closing their accounts.
HSBC says it has reported the loss of the server to the police, the Hong Kong Monetary Authority and the Office of the Privacy Commissioner for Personal Data.
In February HSBC lost a computer disc containing the confidential personal details of around 370,000 UK life assurance customers.
The password-protected disc - which included names, life insurance cover levels, dates of birth and details on whether or not a customer smokes- went missing after being sent by external courier from HSBC's Southampton offices to a reinsurance firm in the UK.