Swiss Buyout Titans Make Progress in Bid to Prevent EU Deal (1)

The founders of private equity firm Partners Group Holding AG have taken a step closer to making it harder for Switzerland to pass a new deal to reorganize relations with the European Union.

Switzerland is due to hold a national vote on the accord, and an organization backed by Alfred Gantner, Marcel Erni and Urs Wietlisbach want a higher bar for approval. The group has collected enough signatures — more than 111,000 — to hold a separate plebiscite on the rules of the vote on the EU deal, the government said Tuesday.

Gantner, Erni and Wietlisbach are among the ...