"They obtained a lot of information about various Swiss banks from the participants in the voluntary disclosure programs and that has likely enabled the recent indictments we've seen," he said. "More people than we saw previously have come to us looking to renounce their citizenship."
Attorney Robert Katzberg, who represents clients in criminal tax cases, said U.S. taxpayers with Swiss accounts don't understand that the IRS and Justice Department will get a trove of new data on secret accounts.
"There are thousands of Americans, who are the functional equivalent of residents of New Orleans on the eve of Hurricane Katrina, who have no idea that Katrina is about to happen," said Katzberg, of Kaplan & Katzberg in New York.