Britain's revenue and customs service is examining allegations that criminals may have used offshore accounts with HSBC, Europe's biggest bank, to launder money, it confirmed Friday.
Her Majesty's Revenue and Customs said in a statement that it had been contacted about a leaked list of the bank's customers, and accusations in a British newspaper that the clients include drug dealers and gun runners.
"We can confirm we have received the data and are studying it. We receive information from a very wide range of sources which we use to ensure the tax rules are being respected," the HMRC said.
In a report published Friday, the Daily Telegraph newspaper alleged that a list of the bank's disclosed by a whistleblower had identified 4,388 people holding 699 million pounds ($438 million) in offshore current accounts, including criminals.
Banks have an obligation to notify authorities about suspicions over the source of cash deposited in its accounts.
HSBC said it was committed to "the highest global standards, including the procedures for the acceptance of clients" and confirmed that it had opened its own inquiry into the alleged data breach.
"We are investigating the reports of an alleged loss of certain client data in Jersey as a matter of urgency," the banks said in a statement.
However, it said it had so far not been contacted by the HMRC about any investigation into its work. "Should we receive notification, we will cooperate fully with the authorities," the bank said.
Jersey, a British dependency off the coast of France which has its own currency and tax laws, is a major offshore financial center.
HSBC said on Monday that it had set aside $1.15 billion to cover potential U.S. fines for money laundering by its Mexican unit and penalties for mis-selling payment protection insurance.
Announcing the decision alongside a 52 percent fall in third-quarter profit to $2.5 billion, the bank said it had raised its total provision for money laundering fines by $800 million to $1.5 billion, though it warned that the cost could go even higher.