Epic Games, Inc. formerly Potomac Computer Systems and later Epic MegaGames, Inc. is an American video game development company based in Cary, North Carolina, partially owned by Tencent. Founded in 1991, it is best known for the development of Unreal Engine technology, which has powered its in-house Unreal, Gears of War and Infinity Blade series as well as many other games, and has been awarded by Guinness World Records as the "most successful video game engine". Epic Games owns video game developer Chair Entertainment and cloud-based software developer Cloudgine, and operates eponymous sub-studios in Seattle, England, Berlin, Yokohama and Seoul. Key personnel at Epic Games include chief executive officer Tim Sweeney, lead programmer Steve Polge and art director Chris Perna. Tencent acquired a 40% stake in the company in 2012, after Epic Games realized that the video game industry was heavily developing towards the games as a service model.