Gabe Newell, co-founder and president of video game developer and digital distribution giant Valve, is among the United States' 100 richest people, according to Forbes (via Gamesindustry.biz).
Newell made it to the 97th position on the Forbes 400 list, worth an estimated $5.5 billion. As Gamesindustry points out, Newell's wealth has gone up about five times in size since 2013, when it was reported his wealth was at $1.1 billion. While Valve doesn't post its financials publicly, Forbes estimates Newell owns more than half of the company. For comparison, Forbes' current richest American is Bill Gates, who has $89 billion.
Newell's success, in no small part, can be credited to Steam, which Valve has claimed has 125 million active users. Furthermore, Valve is the developer and publisher of such games as Dota 2, Team Fortress 2 and Counter-Strike: Global Offensive – all huge successes in the ever-growing esports world.
Newell founded Valve alongside former Microsoft co-worker Mike Harrington in August 1996. The company soon found success with its groundbreaking first person shooter Half-Life, which spawned a sequel many consider one of the best games of all time. Since then the company's developed numerous successful games, such as the Portal series, as well as launched Steam and its own PC console box, the Steam Machine.