Former HSBC employee accused of stealing data on 24,000 Swiss bank accounts

The former IT employee of Swiss subsidiary HSBC Private Bank (Suisse) SA, identified by French authorities as Herve Falciani, allegedly obtained the information between late 2006 and early 2007, the bank said. The accounts, owned by individuals worldwide, were all opened prior to October 2006 and some 9,000 have since been closed.

The data theft only affects accounts in Switzerland with the exception of its former subsidiary HSBC Guyerzeller Bank.

"We deeply regret this situation and unreservedly apologize to our clients for this threat to their privacy," said Alexandre Zeller, chief executive of the Swiss subsidiary.

The Swiss Financial Market Supervisory Authority, or FINMA, said Thursday it has launched an inquiry into whether HSBC meets legal requirements to prevent data theft.

The bank has informed the affected customers and ruled out that any unauthorized person could access the accounts in question. But, it is feared the incident may leave large numbers of international account holders exposed to prosecution by tax authorities if they failed to declare the assets in their home countries.