US prosecutors have accused three Swiss bankers of conspiring with wealthy US taxpayers to hide more than $1.2 billion in assets from tax authorities.

The office of the Manhattan US Attorney said in a statement that the indictment charges the bankers with trying to "capture business lost by UBS and another large international Swiss bank in the wake of widespread news reports that the Internal Revenue Service was investigating UBS" in 2008 and 2009.

The charges signal that US authorities are moving closer to criminal charges against some Swiss and Swiss-style banks that sold tax evasion services to rich Americans, according to the sources.

The bank was not identified in the single indictment filed against Michael Berlinka, Urs Frei and Roger Keller. The three men, who reside in Switzerland, worked for the unnamed institution between 2005 and 2010 and sold tax evasion services from the bank's Zurich office, the indictment said.

If convicted, the bankers face a maximum prison term of five years under the conspiracy charge.

US authorities, who suspect that tens of thousands of Americans have been using Swiss banks to avoid paying billions of dollars in taxes, are investigating scores of Swiss banks and international banks with Swiss operations.

Separately, the US Department of Justice is conducting criminal probes of 11 banks, either Swiss or global with major Swiss operations.

The investigations, an outgrowth of scrutiny of UBS, are focused on Credit Suisse AG, HSBC Holdings Plc and Basler Kantonalbank, among others. In 2009, UBS paid $780 million to settle Justice Department criminal charges that the bank helped thousands of US clients hide $20 billion in their accounts.

Swiss authorities want a global civil settlement with US authorities in which the entire Swiss banking industry would pay a fine and shutter their undisclosed private banking services for Americans. That settlement would be handled by the IRS.

Reuters