Christos Bagios is accused of helping an estimated 150 American customers while working for UBS after being arrested during January by the authorities.
Mr Bagios is believed to have managed as much as $500 million in clients accounts between 1999 and 2005.
The criminal complaint, which was quoted by Bloomberg, said: âChristos Bagios and others would and did market undeclared Swiss bank accounts and Swiss bank secrecy to wealthy US clients who were interested in attempting to evade United States income taxes.â
According to reports, the charge is thought to be separate to those brought against four former Credit Suisse employees last week.
Marco Parenti Adami, Emanuel Agustino, Michele Bergantino and Roger Schaerer are the men accused of helping US customers avoid paying tax through secret bank accounts.
Previously, UBS paid $780 million in fines after it admitted helping clients avoid paying tax to the Internal Revenue Service.
The bank also handed over details of the accounts to the authorities.