Valve Corporation
Logo
Type	Private
Industry	Computer software Interactive entertainment
Founded	Kirkland, Washington, U.S.(1996)
Founder(s)	Gabe Newell Mike Harrington
Headquarters	Bellevue, Washington, U.S.
Area served	Worldwide
Key people	Gabe Newell (Managing director)
Products	Half-Life series Counter-Strike series Day of Defeat series Team  Fortress series Left 4 Dead series  Portal series Source Steam Valve Anti-Cheat
Services	Valve Cyber Café Program
Total equity	US$2.5 billion (2012, estimated)
Employees	~400 (2012)
Subsidiaries	Valve S.a.r.l.
Website	www.valvesoftware.com

Valve Corporation (formerly Valve Software, commonly referred to as Valve; stylized as VALVE) is an American video game development and digital distribution company based in Bellevue, Washington, United States. Founded in 1996 by former Microsoft employees Gabe Newell and Mike Harrington, Valve became famous for its critically acclaimed Half-Life (released in November 1998) and Portal series (released in October 2007). It is also well known for its social distribution network Steam, and the Source engine, which has been used in every Valve game since its introduction in 2004.

History
Valve was founded by long-time Microsoft employees Gabe Newell and Mike Harrington on August 24, 1996 as an L.L.C. based in Kirkland, Washington. After incorporation in April 2003, it moved from its original location to Bellevue, Washington, the same city in which their original publisher, Sierra On-Line, Inc., was based.

After securing a license to the Quake engine (through the help of friend Michael Abrash of id Software) in late 1996, Newell and Harrington began working on Half-Life. Originally planned for release in late 1997, Half-Life launched on November 19, 1998. Valve acquired TF Software PTY Ltd, the makers of theTeam Fortress mod for Quake, in May 1998 with the intent to create a standalone Team Fortress game. The Team Fortress Classic mod, essentially a port of the original Team Fortress mod for Quake, was released for Half-Life in 1999. Gearbox contributed much after the release of Half-Life. Gearbox Software is responsible for the Half-Life expansion packs, Half-Life: Opposing Force and Half-Life: Blue Shift, along with the home console versions of Half-Life for the Sega Dreamcast and Sony PlayStation 2 which included a third expansion pack called Half-Life: Decay, that enabled two-player split-screen co-op.

After the success of Half-Life, the team worked on mods, spin-offs, and sequels, including Half-Life 2. All current Valve games are built on its Sourceengine, which owes much of its success to mods and sequels. The company has developed six game series: Half-Life, Team Fortress, Portal, Counter-Strike, Left 4 Dead and Day of Defeat. Valve is noted for its support of its games' modding community: most prominently, Counter-Strike, Team Fortress, and Day of Defeat. Valve has branched out with this tradition to continue developing Dota 2 as the stand-alone sequel to the Warcraft III mod. Each of these games began as a third-party mod that Valve purchased and developed into a full game. They also distribute community mods onSteam.

Since Valve Corporation's debut, it has expanded both in scope and commercial value. On January 10, 2008, Valve Corporation announced the acquisition of Turtle Rock Studios. On April 8, 2010, Valve won The Escapist Magazine's March Mayhem tournament for the best developer of 2010, beating out Zynga in the semi-final and BioWare in the finale.

On August 1, 2012, Valve Corporation announced revisions to the Steam Subscriber Agreement (SSA) to prohibit class action lawsuits by users against the service provider. Alongside these changes to the SSA, the company also declared publicly the incorporation of Valve S.a.r.l., a subsidiary based in Luxembourg.

Valve's internal network has been infiltrated by hackers twice, once in 2003 where content of yet to be released Half-Life 2 was leaked onto the internet, and again in 2011 when the Steam customer databases were compromised.