(BERLIN) — Volkswagen, the world’s top-selling automaker, lost a stunning 17.1 percent of its value Monday after admitting that it intentionally rigged nearly half a million cars to defeat U.S. smog tests. The Obama administration, meanwhile, announced it is expanding its investigation of what it’s calling “defeat devices” in diesel vehicles, to make sure other manufacturers aren’t using similar schemes to thwart federal Clean Air laws. Volkswagen has now admitted that it intentionally installed software programmed to switch engines to a cleaner mode during official emissions testing.