A former UBS private banker jailed in the US after assisting in the pursuit of tax evaders intends to petition the President for a commutation, according to media reports. He also wants a substantial reward under a federal “whistle-blower” programme.

Bradley Birkenfeld, who was at UBS’s cross-border unit in Geneva for about five years, started a 40-month sentence for conspiring to defraud the government in August last year.

It is believed the petition will be filed today, stating inter alia: “Mr Birkenfeld provided an unprecedented and unmeasurable benefit to the public” and that “commutation will encourage other whistle-blowers to come forward without fear of prosecution. His continued imprisonment will harm future compliance with tax laws, especially as they relate to illegal offshore accounts.”

Birkenfeld's revelations helped plunge UBS into a high-profile dispute with US authorities. The Swiss bank last year paid a $780 million fine to settle criminal charges it helped US clients evade tax and the US and Swiss governments have agreed a deal under which UBS will transfer up to 4,450 client accounts to the US. However, the latter deal, part of a separate civil case, has been potentially derailed by a ruling by a senior Swiss court.