GM purchased a percentage of Isuzu. I don't know the numbers but it's enough to give GM power to manipulate Isuzu. You'll find that Isuzus use some GM parts, and some models of Isuzus are just rebadged GM trucks. A.K.A The Ascender (Trail Blazer) and the Hombre (S10). From what I understand, the relationship between Isuzu and GM has been a rocky one too.