VW owns Audi, Seat, Skoda, Bentley, Bugatti and Lamborghini.
Nissan owns Infiniti.
Toyota owns Lexus and Daihatsu.
And there's probably way more than that.
Edit:
Even better...
BMW
-Mini
-Rolls Royce
DaimlerChrysler
-Chrysler
-Dodge
-Eagle (brand discontinued)
-Hyundai (DaimlerChrysler only owns a percentage) -Jeep
-Maybach
-Mercedes-Benz
-Mitsubishi (DaimlerChrysler only owns a percentage)
-Plymouth
Fiat
-Ferrari
-Maserati
Ford
-Aston Martin
-Jaguar
-Land Rover (recently bought from BMW)
-Lincoln
-Mazda (Ford only owns a percentage)
-Mercury
-Volvo cars
General Motors
-Buick
-Cadillac
-Chevrolet
-Daewoo
-GMC
-Hummer
-Isuzu (GM only owns a percentage)
-Oldsmobile (brand discontinued)
-Pontiac
-Saab
-Saturn
-Subaru (GM only owns a big percentage)
-Suzuki (GM only owns a small percentage)
Honda
-Acura
Hyundai
-Kia
Nissan
-Infiniti
Porsche -They do a lot of work with VW but Porsche remains its own company
Renault
-Nissan (Renault owns a percentage)
Toyota
-Lexus
-Scion
Volkswagen
-Audi
-Bentley
-Bugatti
-Lamborghini
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