UBS Group AG has warned over the impact of the surging Swiss franc and negative interest rates in Switzerland and the eurozone, sending its shares down more than 3 percent in early trade. Switzerland’s biggest bank said a sudden move by the central bank to abandon a cap on the franc, which sent the currency surging and is set to make life difficult for Swiss financial firms and exporters, will take a toll. “The increased value of the Swiss franc relative to other currencies, especially the U.S.