Wegelin, the oldest Swiss private bank, pleaded guilty in Manhattan federal court on January 3 to charges of helping wealthy Americans evade taxes through secret accounts and then announced it would close down as a result.

U.S. District Judge William Pauley in Manhattan granted the IRS's request to issue a "John Doe" summons, which seeks information about possible tax fraud committed by individuals whose identities are not known, on UBS for the names of taxpayers who may have hidden income at Wegelin and other Swiss banks.

A UBS spokeswoman declined to comment on the ruling.

When the government indicted Wegelin nearly a year ago, it alleged that the bank used a U.S. correspondent account at UBS to handle funds for American clients, a standard industry practice for foreign banks. By covertly transferring money from undeclared Swiss accounts, Wegelin allowed clients to avoid paying income taxes in the United States, the government alleged.

Wegelin became the first foreign bank in recent memory to be indicted by U.S. authorities last February, opening a new chapter in a broad probe into Swiss bank secrecy. As part of its guilty plea, the bank agreed to pay $57.8 million in fines after admitting to helping U.S. clients evade taxes on at least $1.2 billion for more than a decade.

It announced on the same day that it would shut its doors permanently after more than 270 years in operation.

In 2009, UBS entered into a deferred-prosecution agreement, turned over 4,450 client names and paid a $780 million fine after admitting it provided tax-evasion services to rich Americans. Since then, dozens of Swiss bankers and their clients have been indicted in a crackdown on the practice.

(Editing by Tim Dobbyn, Bernard Orr and Edmund Klamann)

By Joseph Ax