The investigation concerns historical private banking services provided on a cross-border basis to US persons, and the bank received a letter notifying it that it was also being investigated, media reports said.

“As previously disclosed, Credit Suisse has been responding to requests for information, including subpoenas, in an investigation by the US Department of Justice (DoJ) and other US authorities,” the bank said in a statement on its corporate website.

“The investigation concerns historical private banking services provided on a cross-border basis to US persons. As part of this process, on 14 July, 2011, Credit Suisse received a letter notifying it that it is a target of the DoJ investigation. It has been reported that the US authorities are conducting a broader industry inquiry. Subject to our Swiss legal obligations, we will continue to cooperate with the US authorities in an effort to resolve these matters,” the statement added.

The story highlights how US authorities have targeted a range of banks in their hunt for alleged tax evaders. In February 2009, Credit Suisse’s Zurich-listed rival, UBS, had to pay a $780 million fine to settle criminal charges that it helped wealthy US citizens evade tax and later that year, as part of a civil case, it handed over client account details to the US. The move was seen as a historic breach of Switzerland’s centuries-old bank secrecy laws. Tax evasion, in contrast to practice in many nations, is not regarded as a crime under Swiss law.

A number of banks, including UBS, Wegelin and Julius Baer, no longer provide offshore banking services to the US.

It is not just Swiss banks that have come under the microscope. HSBC has come under investigation, as reported earlier this year.