That's according to sources familiar with the matter who tell Bloomberg letters have already been sent to Epic Games and Riot Games by the Committee on Foreign Investment in the US. Chaired by the Treasury Department, the CFIUS investigates potential national security risks that stem from foreign businesses acquiring or investing in American businesses. League of Legends developer Riot Games is wholly owned by Tencent, while the Chinese games giant has a 40% stake in Fortnite firm Epic Games.