Zynga, the publisher of Facebook games such as Farmville, Mafia Wars and Texas HoldEm Poker, has not yet filed for an IPO, so its worth is yet unknown. However, research company NeXt Up! analysts have used expected compound annual growth to calculate the company's worth between $2.8 and $3.3bn.

Zynga's user base increased from 30 million people in April 2009 to 228 million in January 2010.

With a significant presence on social networking sites such as Facebook, MySpace and Bebo, as well as iPhone apps, Zynga primarily makes money through in-game advertising and marketing offers, though the report stated that 40 per cent of Zynga's revenue comes from the sale of virtual goods.

The study is available on pre-IPO trading website SharesPost.

"We have used two methods," said the report. "Steady-state target EV/Revenue multiple, and comparative EV/Revenue multiple based on a peer group. We arrived at a market cap of $2.806 billion to $3.315 billion for Zynga, and an estimated price per share of $14.97 to $17.68."

The report projects revenue of $460m for Zynga this year, growing to $1.1bn in 2014.