Forbes has published an interview with Gabe Newell, the founder of game publisher Valve. As a private company, Valve isn't required to release details about its financial state but Newell said Valve is tremendously profitable and added that per head, Valve is more profitable than Google and Apple.
The 250-person company releases no financials but, according to Newell, is "tremendously profitable." Ed Barton, a games analyst at IHS Screen Digest, estimates that Valve's revenue in 2010 was in the "high hundreds of millions of dollars." (A 2005 FORBES story on Valve had the company grossing $70 million with a fat $55 million in operating profit.)
Valve announced last October that it was on track for its biggest year ever, with 200% year-over-year growth. Newell says that, per employee, Valve is more profitable than Google and Apple. A potential buyer was rumored to have made an acquisition offer a few years back for the Steam piece only, but Newell supposedly refused to split the online storefront from Valve's game-publishing arm. (Valve denies being made an actual offer, only confirming that it received interest in both Steam and Valve in the past.)