Pretty sure that's 20% of revenue, and I'm assuming that their business plan relies on skimming from settlements, not just taking donations. But they are also paying investigators and lawyers out of all of that.
Whistleblowers take all of the risk here, and only get 20% of the proceeds. Seems like a pretty shit deal, besides being confoundingly greedy.
There already are people you can trust, who aren't anonymous, who are professionals bound by ethics, and who aren't out to sue for profit: Journalists. investigations@icij.org