In my opinion (not investing advice!), they're (investors) exiting now via IPO because their brightest days are behind them. If they're raking in money without millions of shareholders, why would they IPO? They'll paint a rosy picture based on recent performance to pull in several billion dollars, cash out, and move on to the next project. Very, very few game companies make money in the long run ("long" being 5+ years).

Well they've positioned themselves well for the IPO by doing the trademark grab recently. If courts continue to allow them to assert their dominance I think they'll continue to make decent money for a while. I would agree that they're not a long game investment but I think they'll make it over 5 years.

Why not look for someone else to be left holding the bag when the mobile game playing public loses interest in Candy Crush? a la OMGPop/Draw Something selling to Zynga.