Zynga generated $445m for Facebook in 2011

FarmVille, CityVille and the rest of Zynga’s portfolio are well-established as Facebook’s money-makers and now we know how much they are truly worth.

Paperwork filed by Facebook ahead of its IPO shows that the social games firm accounted for 12 per cent of the $3.7bn revenues the site took in 2011 – that’s roughly $445m, Gamasutra reports.

This figure encompasses direct advertising from Zynga, impressions from ads around the company’s games and pages, and Facebook’s 30 per cent share of all microtransactions.

However, Facebook warned potential investors that any disputes between the two companies could present a significant risk to the social networking site in the future.

Facebook said in the filing: "If the use of Zynga games on our platform declines, if Zynga launches games on or migrates games to competing platforms, or if we fail to maintain good relations with Zynga, we may lose Zynga as a significant platform developer and our financial results may be adversely affected."