Did American companies such as IBM, I.G. Farben, J.D. Rockefeller’s Standard Oil Company, and the Union Banking Corporation of New York City help the Nazi war effort?
Before other responses come in, you might be interested in this response by u/kieslowskifan answering a very similar question.
P.S. Just to make things straight, I.G. Farben was a German rather than American company.