The company, which is the top publisher of games on Facebook such as "FarmVille" and "CityVille", sold 100 million shares raising $1 billion, the source told IFR on Thursday.
At $1 billion, Zynga's IPO would be the largest from a U.S. Internet company since Google Inc raised $1.7 billion in 2004.
Based on a fully diluted share count of 890 million shares, the IPO values Zynga at $8.9 billion.
Zynga is selling about 11 percent of diluted shares in the offering.
Zynga had previously been targeting a share price of $8.50 to $10.
Underwriters on the deal were lead by Morgan Stanley and Goldman Sachs.
The International Finance Review is owned by Thomson Reuters.
(Reporting By Liana B. Baker, editing by Bernard Orr)
Copyright 2011 Thomson Reuters. Click for Restrictions.
The Morning Email helps you start your workday with everything you need to know: breaking news, entertainment and a dash of fun. Learn more