Um, let's see if I'm on the ball:
Ford owns Jaguar, Lincoln, Mercury, Volvo.
GM owns Saab, Pontiac, GMC, Chevy, Oldsmobile.
Volkswagon owns Audi.
Toyota owns Lexus, Scion.
Honda owns Accura.
Nissan owns Infiniti.
Porsche owns Porsche.
I know I'm forgetting some.