03/26/2009 05:12 am ET Updated May 25, 2011

UBS: Revealing Identities Is Illegal

Switzerland's largest bank accused the US government of ignoring Swiss sovereignty and forcing its employees to break the law.

"The IRS petition does not acknowledge these restrictions and instead simply ignores the existence of Swiss law and sovereignty," the firm's lawyers said in a response to the filing.

The comments come after the US government filled lawsuit on Thursday to force the bank to reveal the identities of as many as 52,000 Americans who allegedly evaded taxes.

Meanwhile, UBS stock swung to an all-time low on Monday due to its handling of the US tax fraud probe.