This is not a historical question. My opinion is that american companies were deeply reprehensible for their contributions ("selling" on credit), to the fascist states particularly. Nonetheless, this is not really an appropriate question for this forum.

This question has been removed because it violates the rule on poll-type questions. These poll-type questions do not lend themselves to answers with a firm foundation in sources and research, and the resulting threads usually turn into monsters with enormous speculation and little focussed discussion. “Most”, “least”, "best" and "worst" questions usually lead to vague, subjective, and speculative answers. If you'd like, you may PM /u/caffarelli to have your question considered for an upcoming Tuesday Trivia thread.