Valve has hired two former PopCap employees who were part of the team behind Plants vs. Zombies, according to Shacknews. Star Filled Studios co-founders Tod Semple and Jeff Gates, both of whom also worked on Diablo III at Blizzard, were laid off from PopCap in August.
Previous reports, including a quote from Valve co-founder Gabe Newell, indicated Semple and Gates would would form a Valve subsidiary in the San Francisco Bay Area. However, Valve's Doug Lombardi has since clarified that "this is probably better categorized as Valve hiring two new employees instead of an acquisition of a company or opening of a Valve SF office."
The last company Valve acquired was Turtle Rock Studios, which brought in Left 4 Dead before reopening as an independent operation in 2009.