Data theft at HSBC hits Swiss clients

London/Geneva: HSBC said a theft of data by a former employee affected up to 24,000 Swiss client accounts, dealing a hefty blow to the reputation of its private bank.

The bank had previously said "less than 10 clients" were affected after Herve Falciani — a former HSBC computer specialist — stole client data from the bank which he handed over to French tax authorities.

"The theft, which was perpetrated by a former IT employee about three years ago, involves approximately 15,000 existing clients who had accounts with the bank in Switzerland before October 2006," HSBC said in a statement.

On top of that, up to 9,000 accounts that had been closed in the past were affected. These accounts often were not big enough to be eligible for private banking services, the bank said. It has 100,000 clients in Switzerland.

HSBC shares were down 0.4 per cent, just underperforming the European banking sector. The controversy comes at a sensitive time for the secretive sector — which serves rich clients — with countries sometimes using stolen client data to chase tax evaders, a practice one Swiss lawmaker has likened to bank robbery.

Swiss banking giant UBS has seen billions of Swiss francs of client money gush from its wealth management operations.