Taxpayers who still believe they can hide secret Swiss bank accounts from the IRS are “beyond foolish,” the top United States tax prosecutor said as a five-year crackdown expands to new offshore havens.

The enforcement drive has forced a “remarkable” change in the ability of the U.S. to find secret accounts in Switzerland, the world’s largest offshore financial center with about $2.2 trillion of assets, said Kathryn Keneally, assistant attorney general in the Justice Department’s tax division.

“If someone had an account in Switzerland, it is beyond foolish to think that that account is going to remain secret,” said Keneally, 55. “In the last five years, we’ve seen a remarkable change in our ability to get information concerning Swiss bank accounts. It’s extraordinary. Switzerland is no longer a good place to hide assets for tax reasons.”

Keneally, in her first interview since taking the job in April 2012, said a new U.S. amnesty program for Swiss banks to disclose how they aided tax evasion puts taxpayers and offshore enablers at risk of prosecution.

Since 2009, the U.S. has prosecuted 68 U.S. taxpayers, 3 Swiss banks, and 30 bankers, lawyers, and advisers. Another 38,000 Americans moved $5.5 billion to the U.S. and avoided prosecution by saying who helped them offshore. Read More