Forbes declares Valve's Gabe Newell "The Newest Video Game Billionaire" in an article on the success of Valve and Steam. They admit that they can't know the true financial state of Valve, which is privately owned, but they offer a "conservative" estimate that's pretty eye-popping: "Even the most conservative estimates put Valve’s enterprise value at more than $3 billion, and since Newell owns more than 50% of the company, that means he’s worth at least $1.5 billion."