Litigation financing has become more prominent in the USA in recent years. Instead of having your lawyer assume all the risk, you go to a lender who is willing to take some kind of security in your cause of action. It's not exactly a loan per se since you don't have to pay back the advances in most cases (quite possibly to
avoid meddling).
I don't know how they run the numbers on these things, but I can't imagine such providers are willing to take on a lot of risk with little reward. You might even be giving up a bigger chunk of any potential award than if you were to enter into a contingency fee arrangement with your lawyer.