According to a report published today in the New York Times, Electronic Arts offered more than a billion dollars in an attempted buyout of Valve, but was ultimately turned down by the PC gaming company.
The sources asked to remain nameless, but both confirmed that EA had made a billion dollar pass at the Half-Life, Portal, Team Fortress, Dota 2, Counter-Strike, Left 4 Dead and Steam creator. Valve figurehead Gabe Newell was quoted as saying he'd rather let the company disintegrate over time than sell out to a mega corporation.
“It’s way more likely we would head in that direction than say, 'Let’s find some giant company that wants to cash us out and wait two or three years to have our employment agreements terminate'.”
There is no word on when this attempted buyout may have taken place, but Valve is apparently currently valued at $2.5 billion. Which seems to indicate this was an event that took place some time ago before Steam became such a runaway success. It's possible (though entirely speculation) that EA sought to buyout the market leader in PC digital distribution before developing their own solution, Origin.