U.S. authorities say a Swiss banker has admitted to helping U.S. citizens evade their taxes, thereby conspiring to defraud the U.S. Internal Revenue Service (IRS).

The U.S. Department of Justice said that Josef Dörig, 72, of Switzerland, pled guilty today to conspiring to defraud the IRS in connection with his work as the owner of a trust company in Switzerland. He will be sentenced on Aug. 8, and faces a statutory maximum of five years in prison.

In a statement of facts filed with the plea agreement, Dörig admitted that between 1997 and 2011, he engaged in a wide-ranging conspiracy to help U.S. customers evade their income taxes by concealing assets and income in secret bank accounts held in the names of sham entities.

“Today’s plea further pulls back the curtain on efforts by Swiss banks to help U.S. taxpayers evade taxes through the use of sham trusts and foundations,” said deputy attorney general, James Cole. “Rest assured, the days of bank secrecy for U.S. tax cheats in Switzerland – and around the world – are numbered.”

“We will continue to investigate and prosecute banks and individuals who assist U.S. citizens in the evasion of income taxes with overseas accounts,” said U.S. attorney Dana Boente. “The doors are quickly closing on this illegal activity.”

In the past couple of years, Canadian authorities have also been stepping up their enforcement of offshore tax avoidance efforts. Among other things, the government has launched an offshore tax informant program that allows the Canada Revenue Agency (CRA) to make financial awards for information related to major international tax non-compliance, while also beefing up the CRA’s enforcement capabilities.