HSBC, Europe's largest bank said yesterday that data of 24,000 customers was stolen by a former employee of its Swiss subsidiary HSBC Private Bank (Suisse) SA in Geneva three years ago.
Last year the bank had said that it discovered data theft, which it believed affected less than 10 customers, but it said yesterday that the theft was far more serious, and 24,000 customer accounts have been compromised.
One of HSBC Private Bank's former IT employee, identified by French authorities as Hervé Falciani, stole the data pertaining to clients who had accounts with the bank before October 2006, over a period of several months during 2006-2007.
Hervé Falciani, a French national, was forced to hand over the data to his country's tax authorities based on a Swiss search warrant.
The theft had triggered a short diplomatic row between Switzerland and France in December 2009 since France was not keen on handing the data back and wanted to know if any of its citizens had evaded paying tax in France by keeping money in HSBC Private Bank.
The bank realised the extent of the theft, when earlier this month copies of a significant portion of the data was returned to the bank on 3 March 2010 by the Swiss Federal Prosecutor.