UBS AG of Zurich said a senior private banker held in the U.S. and asked to testify before a Senate subcommittee investigating alleged tax evasion has been permitted by U.S. authorities to leave the country.

Martin Liechti, the Zurich-based head of North and South America for UBS's international wealth-management business, has "resolved his status with the U.S. government and returned to Switzerland," the bank said.