Timothy A. answered 05/18/19
Don't go to any college - go to the RIGHT college for you. Talk to me
Well, the Russians actually got it right for once.
The American oil company Standard Oil, through it's South American subsidiaries sold oil to Germany through a series of cutout companies and ruses pretty much throughout the war. This did not go unnoticed by the U.S. Government, and various players in the government wanted to bring John D. Rockefeller (the president of Standard Oil), up on charges of treason, but this was blocked by the Pentagon because Standard Oil powered their war machine too. More importantly though, Standard Oil had a long standing relationship with a German company called IG Farben and IG Farben figured out a process to create oil from coal. This became crucial later to the German war machine as the tide turned against them and they started losing access to traditional oil fields. It was almost solely this coal-fuel that powered the German war machine the last year of the war, which happened to also be the bloodiest year of the war. Without it, Germany might have had to surrender up to a year earlier simply because they would have run out of fuel. Various Congressional hearings and committees looked into this Standard Oil "trading with the enemy" activity during and after the war, but the only thing that ever happened to Standard Oil were some small fines.
For a nice in-depth write up of this, see..