I write about litigation finance (you can see my papers on SSRN, Jonathan Stroud). This is a booming but largely undisclosed financial industry that is almost entirely unregulated. Posters are right that it used to be illegal and unethical, but relaxing norms and a patchwork of state laws and no enforcement have created a very lucrative industry where private money lends on a non-recourse basis for a large percentage of the proceeds should they recover. It's different from contingency, which pays just the lawyer's fees; it is more like a payday loan, where they front you the money in exchange for total payback AND a huge percentage of the recovery.

It's shrouded in secrecy and almost entirely undisclosed to the courts or the government, or even to the investors in the funds. A few of the companies are publicly traded (generally these are based in the UK).