GM doesn't own Subaru. Subaru is owned by Fuji Heavy Industries Ltd. (Aerospace Manufacturer in Japan). Just as Fiat Auto Spa of Italy, Isuzu Motors Ltd. and Suzuki Motor Corp. of Japan, GM collaborates with them in various product, powertrain and purchasing (raw materials like sheet metals). GM also collaborates (not own) with BMW AG of Germany and Toyota Motor Corp. of Japan, and vehicle manufacturing ventures with several automakers around the world, including Toyota, Suzuki, Shanghai Automotive Industry Corp. of China, AVTOVAZ of Russia and Renault SA of France. Now, if someone still insist that Subaru, Suzuki, Opel, Isuzu is owned by GM, then Fiat is also owned by GM which owns Ferrari, Maserati. Wow, a Ferrari made by GM . Again, GM doesn't manufacture the above vehicles but collaborates and or distributes such vehicles (GM Network.)
Now...
GM is the manufacturer of Buick, Cadillac, Chevrolet, GMC, Holden, HUMMER, Oldsmobile, Opel, Pontiac, Saab, Saturn and Vauxhall. GM doesn't just play as a manufacturer of vehicles, they are also involved in vehicle
distribution (but not manufacture), that is why some people
misinterpreted GM as the manufacturer of such vehicle.
but how come Subaru, Fiat, Isuzu, and Suzuki shows up as part of GM's Auto brands in their website?
Because they are the
DISTRIBUTOR of such vehicles on countries other than their originating country such as Japan.