SOFIA—Bulgaria’s GERB party of former long-serving Prime Minister Boyko Borissov is set to win Sunday’s election, the fourth in less than two years, partial results showed, but its chances of forming a coalition government remain unclear.
With 99 percent of the ballots counted, partial official results showed GERB winning with 25.4 percent. Its main rival, the reformist We Continue the Change of Kiril Petkov, whose coalition cabinet collapsed in June, came second with 20.2 percent.
