The Norwegian state, Sweden's Saab and the Wallenberg group have acquired 40 per cent of the offshore firm Aker Kvaerner, Economy Minister Dag Terje Andersen said Friday in Oslo. The previous owner of the shares, Kjell Inge Rkke, earned 4.8 billion kroner (806 million dollars) in the deal, Andersen said. With 21,000 employees, Aker Kvaerner is one of the world's largest builders of rigs for oil and gas exploration at sea. The state's purchase of shares in the company was to ensure that Aker Kvaerner remains under Norwegian control for at least 10 years, Andersen said. Already in spring, Rkke had sold his majority shares in Europe's largest shipbuilding company Aker Yards to international investors. Norway now owns 30 per cent of the company, while Saab has 7.5 per cent and investors Wallenberg 2.5 per cent, the news agency "DPA" reported.