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)
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