Valve Corporation

Valve Corporation is an American computer game company that has created game anthologies such as Half-Life, Portal, Counter-Strike, Team Fortress, Day of Defeat, Left 4 Dead, Ricochet, Alien Swarm, Dota 2, and Artifact; game engines GoldSrc, Source, Source 2; software: Steam, Valve Anti-Cheat, SteamOS, Steam Audio; as well as hardware: Steam Machines, Steam Controller, Valve Index. It was founded on August 24, 1996 by former Microsoft employees Gabe Newell and Mike Harrington.