The alleged theft of information about thousands of HSBC Private Bank customers and their accounts from a branch in Switzerland is likely to grant U. S. tax authority's fresh hints in their search of wealthy tax cheats abroad.

The bank yesterday posted that a former IT employee is alleged to steal information linked to 24,000 clients and former customers.

French authorities have reportedly acquired the data, which includes names, account numbers and some addresses of 15,000 existing HSBC customers and 9,000 who have closed their accounts.

French tax authorities are revealed to analyze data on the 3,000 French account holders on the list.

U. S. authorities are expected to negotiate with the French via a treaty request to get the names of any U. S. clients, lawyers revealed on Friday.

"To the extent the HSBC data includes U. S. based taxpayers having interests in HSBC foreign accounts, it is a virtual certainty such information will be delivered to the U. S. government," said Chuck Rettig, an attorney representing U. S. clients of UBS, HSBC and others who held previously undisclosed accounts.