An executive at Switzerland's biggest bank, UBS, has been charged with conspiring to help customers in the United States commit tax evasion.
In an indictment made public on Wednesday, Raoul Weil is accused of being part of an effort to help around 20,000 clients hide $20 billion (SFr23.6 billion) in assets in overseas accounts between 2002 and 2007.
UBS allegedly gained $200 million a year in revenue as a result during the five-year period, US justice authorities said in a statement.
The bank is also alleged to have trained desk heads and bankers on how to avoid detection by the authorities using encrypted laptops and "counter surveillance techniques", according to the indictment, returned by a grand jury in Florida.
Weil has temporarily stepped down from his position as head of UBS's Wealth Management International division, the bank confirmed on Thursday. The current head of Wealth Management US, Marten Hoekstra, will assume his duties in the meantime.
Weil's lawyer said the charges were "totally unjustified".
The US Internal Revenue Service and the Department of Justice are investigating whether UBS staff helped wealthy clients evade tax in the country. The bank has pledged to cooperate in the probe.
Earlier this year UBS decided to stop offering offshore Swiss bank accounts to US citizens.
In another case heard in the US this year, former UBS employee Bradley Birkenfeld admitted tax evasion offences. UBS has also had to face litigation in the US over alleged mis-selling of securities. It has settled in a number of cases.