A dispute with France over the possible use of stolen account data from HSBC Holdings' Swiss private bank underlines the need for the Swiss government to clarify the conditions under which the Alpine state will co-operate with other jurisdictions in helping to find alleged tax dodgers, Anne-Marie de Weck, president of the Geneva private bankers group, was quoted as saying.

The French Finance Ministry has data on Swiss bank accounts held by its own taxpayers, including names provided by a former HSBC employee, budget minister Eric Woerth said last month. Switzerland has suspended ratification of a tax treaty with France in protest over the handling of the data.

“France has thrown into question the different legal principles anchored in its own legislation as well as those of the European convention” covering legal assistance between countries, said de Weck, who is also a partner at Lombard Odier. A Swiss law is “the only way to offer the necessary legal security” in the exchange of tax data, she said.

The use of stolen bank data has come up before: the UK and German governments have used information stolen by a former employee of LGT, the Liechtenstein-based private bank.