Shares in Volkswagen (VLKAF) crashed 20% Monday, wiping 16 billion euros ($18 billion) off the company’s value after it was found to have misled U.S. regulators.
Federal and state regulators said Friday that the German company cheated on environmental standards by programming some diesel-fueled cars to turn on emission controls only when being tested.
Volkswagen, recently crowned the world’s biggest carmaker by sales, also owns the Audi and Porsche brands.
The software is installed in nearly 500,000 cars on U.S. roads, including some of its luxury-brand Audi cars.
Regulators have ordered Volkswagen to recall the vehicles. The company said it was halting sales of some cars in the U.S.
Volkswagen stock hit its lowest level in nearly three years, and pulled down shares in other German automakers such as Daimler (DDAIY) and BMW (BAMXY).
Related: Volkswagen hid a car hacking for two years
The VW models affected include the Jetta, Beetle and Golf from 2009 through 2015, the Passat from 2014-2015 as well as the Audi A3, model years 2009-2015. Owners of the “CleanDiesel” automobiles have filed a class action lawsuit against Volkswagen.
Volkswagen CEO Martin Winterkorn apologized to customers on Sunday for breaking their trust.
Volkswagen has enjoyed a reputation for reliability and quality engineering and that is likely to be damaged by the scandal. The automaker may also face fines of billions of dollars over the issue.