Since the mid-2000s the Swiss city has won back market share, executives said. Oil traders said the plans of Rosneft were unclear. In the past, the company has sold some of its output through Gunvor and the rest via competitive tenders. The launch of a trading arm could see an overhaul of the system. "There is a general view that Rosneft are going to restructure the way they handle their export volumes," a senior Geneva-based oil trader said.