This is just a hunch, but I have a feeling that Trumps loans probably came from his own corporations or from foreign banks. Its possible that he used one of his corporations to borrow money from a domestic bank and then turned around and loaned money to himself from those proceeds, which would be consistent with why his audits have gone on for so long. Things get pretty complicated when you are moving money back and forth between personal holdings and corporations that you own. Ive done it several times and my stuff is nowhere near as complex as what Trump has. On top of that, he can make a legitimate case that his brand is an actual business. Because of that, he can make a legal case that doing something like buying a golf course that perennially loses money is actually an asset because by having his name on it improves his brand, which is a legitimate deduction. None of this is as cut and dried as either he is a failed businessman or he is committing tax fraud.
We shall see. I do believe that my money laundering hypothesis (if proven true) will end up being quite cut and dry.