The vote is an important step toward passage of a law that would clear the way for Switzerland to hand over the names of 4,450 US taxpayers who allegedly evaded taxes by hiding money in accounts at UBS AG. Last year, UBS admitted that its bankers helped the Americans dodge taxes by setting up sham corporations, falsifying documents and using Swiss credit cards to access their accounts.

That deal risked falling apart in January after a Swiss court ruled that it broke Swiss law. In February, the government presented a proposal that would lay the legal groundwork for it to hand over the names. The Swiss government is under pressure to see the law passed in time to meet an August deadline to give US authorities the names.