Switzerland's Social Democratic party said it filed a complaint with Zurich prosecutors against former UBS AG Chairmen Marcel Ospel and Peter Kurer in connection with the bank's management of U.S. funds offshore.

The Friday announcement came after UBS and the U.S. government on Wednesday signed a final deal to settle an unprecedented U.S. tax-evasion probe that had sought the names of 52,000 of the Swiss bank's U.S. clients.