The wealthy have offshore accounts. I heard that some of these accounts are listed with pseudonyms. Isn't it possible that Stark could have gotten access to one of those funds, and the villains, not knowing his finances, wouldn't be the wiser about his movements?
I watched the ending credits, and I saw a new scene. The oil executive was seen getting up from the ground. I wonder if the oil executive was keyed into the plan, and was one of the private funders.