UFC, at one point, seemed like the sports game to own. Every gamer I knew who didn't have the time to put hundreds of hours into rich detailed worlds and beautiful landscapes owned a copy of at least the first two THQ-published titles. Apparently the third didn't do nearly as well – it failed to sell two million copies in fact – and it was this that led THQ to approach EA with the idea of the sports division of the latter buying the licence from them.
It's surprising that, with two million copies sold, THQ didn't manage to break even on this one. I can only imagine it's mainly down to licensing fees, I don't know, but it did lead to lay-offs and cutbacks for the publisher. We know, thanks to LinkedIn profiles, that a fourth game in the series was underway before EA bought the licence and began the series anew.