After being fed some recent cow manure on who owns what brands, I thought I'd do some digging and try to clarify which company owns what brands so you have a slightly better idea of what is on your car and where it comes from. I've also done this as a Wiki so people can edit my mistakes or update as appropriate.

I don't know if it's of any use, but I found it interesting.

Parent		Domicile		Brands
Kumho Asiana		South Korea		Kumho, Marshal, Roadchamp, Tyrechamp
Goodyear		US		Goodyear, Dunlop (except Asia and South Africa), Fulda, Debica, Sava
Sumitomo Group		Japan		Dunlop (Asia), Falken, Sumitomo
Apollo Tyres		India		Vredestein, Apollo, Dunlop (South Africa)
Bridgestone Corp		Japan		Bridgestone, Firestone, Dayton
Cooper Tire Co		US		Avon, Cooper, Mastercraft, Dean, Starfire
Continental		Germany		Continental, Uniroyal (except US), Semperit, General, Barum, Viking, Mabor, Matador
Hankook		South Korea		Hankook, Aurora
Michelin		France		Michelin, BF Goodrich, Kleber, Uniroyal (US)
Pirelli		Italy		Pirelli, CEAT
Toyo		Japan		Toyo
Yokohama		Japan		Yokohama
South China Tyre and Rubber		China		Wanli