That just means that if they settle or go to trial and get a win they take a pretty good percentage of the award. They do not take usually questionable cases either that is high speculation of a loss.
If they lose and you get nothing, then they do not get anything in fees other than maybe able to bill for a few expenses. But they also would not be paying the other sides lawyers fees which in this case would be GP's attorneys fees. That is to hopefully stop stupid frivolous law suits hopefully.
Bookmarks