The U.S. luxury car market has been a bonanza for Mercedes and BMW as they have motored from one sales record to another. But the third German luxury brand, Audi, keeps making detours. Despite its backing by corporate parent Volkswagen, pioneering engineering developments like all-wheel drive and a strong performance elsewhere around the world, its stop-and-go efforts have caused it to get lost in the shuffle. Audi has lost money in the U.S. for years.

The U.S. luxury car market has been a bonanza for Mercedes and BMW as they have motored from one sales record to another. But the third German luxury brand, Audi, keeps making detours. Despite its backing by corporate parent Volkswagen, pioneering engineering developments like all-wheel drive and a strong performance elsewhere around the world, its stop-and-go efforts have caused it to get lost in the shuffle. Audi has lost money in the U.S. for years.