Business magazine Forbes has put out its annual list of the world’s 400 richest people–and Valve boss Gabe Newell made the cut. According to the magazine (via Kotaku), Newell is worth $4.1 billion.

A Forbes report from 2012 said Valve the company was worth $3 billion at the time. Given that Newell reportedly owns half the shares in the video game firm, his net worth was estimated to be $1.5 billion then. If the new numbers are accurate, it’s been a good four years for Valve and Newell.

The magazine’s new estimate of $4.1 billion for Newell’s net worth puts him ahead of film director Steven Spielberg ($3.7 billion), entrepreneur Mark Cuban ($3.2 billion), and Oprah ($2.8 billion). Microsoft founder Bill Gates tops the list this year with a net worth of $81 billion, well ahead of the world’s second richest person, Amazon founder Jeff Bezos ($67 billion).

Unlike Activision, EA, Take-Two, Ubisoft, Nintendo, Sony, and Microsoft, Valve is not a publicly traded company. That’s part of the reason why we don’t officially know Valve’s net worth. Some publicly traded companies also disclose their executives’ salaries, but Valve doesn’t do this since it’s private.

You can see Forbes‘ full list of the world’s richest people here.

During a Reddit AMA in 2014, Newell revealed that he donated $1 million to charity. He will hold his next AMA today, January 17, starting at 3 PM PT / 6 PM ET.

Source: GameSpot