A whistle-blower who helped the federal government uncover UBS AG’s strategy for hiding assets of U.S. account holders was handed $104 million by the Internal Revenue Service in possibly the largest ever award to a tax whistle-blower, his lawyers said Tuesday.

Bradley Birkenfeld, a former UBS private banker, detailed a $20 billion tax evasion scheme by the largest Swiss bank and set the stage for the IRS to dismantle some of the world’s tightest banking secrecy laws. Birkenfeld said UBS bankers even hid diamonds in toothpaste containers to help their American clients.