Riot was already bought by Tencent.
Whoever decided to purchase all that stock is probably pretty giddy right now. According to fortune magazine: "The game has over 100 million monthly players, which generate approximately $1.5 billion annually for the Los Angeles-based developer, according to SuperData Research.
[Chinese tech giant Tencent] acquired a majority stake (93%) of Riot Games back in February 2011 for a reported $400 million."
400 million for a company that makes 1.6 billion annually isn't half bad ROI.