An American customer of UBS AG plans to request a Swiss court to stop UBS handing over his account details to US authorities investigating alleged tax evasion.

His lawyer Thomas Fingerhuth said yesterday the Swiss federal tax office had given his client 30 days to challenge its decision that he had to surrender his entire file to the US investigators, who are trying to determine whether UBS helped wealthy Americans evade their tax obligations.

'It's my contention that the documents were compiled illegally, and therefore cannot be surrendered or used in America, where the rules on permissible evidence are much stricter than in Switzerland anyway,' Fingerhuth told The Associated Press.

He said several other UBS clients were preparing similar cases, but this was the first. 'In my client's case, it's not about a crazy amount of money,' Fingerhuth said. 'But I have a feeling that they want to push through one case to see how it goes, and then follow through with the others.'

Further reading:

UBS director charged with tax evasion

UBS looks to settle private banking tax issues