Jersey's financial regulator has launched an investigation into HSBC's operations on the island following allegations that the bank opened offshore accounts for serious criminals.
The Jersey Financial Services Commission said it would "examine in detail" anti-money laundering systems and controls executed by HSBC. The JFSC will also investigate how details of thousands of accounts held at the bank's Jersey unit were leaked to HM Revenue and Customs.
On Friday, news emerged that HMRC had been handed details of more than 4,000 HSBC clients in Jersey.
The account holders are believed to include Daniel Bayes, a drug dealer now living in Venezuela, Michael Lee, who was convicted of possessing more than 300 weapons at his house in Devon and three bankers facing fraud allegations.
The disclosure came less than a week after the bank said it had set aside $1.5bn (£944m) to cover fines for United States regulatory breaches, including a failure to stop Mexican drug money laundering.
Responding to yesterday's news, HSBC said: "We are aware of JFSC's announcement today and will cooperate fully. We are pleased that the JFSC will look into how the misappropriation of data occurred, and apologise again to our customers for this."
The bank has already opened an investigation into the leaked documents and has visited Jersey to meet the island's regulators.
Last week, HMRC said it was "studying data" understood to have been sent by a whistleblower. "We value the information we receive from the public and business community," it added.