The maker of popular Facebook games including FarmVille and Mafia Wars says this morning in an SEC filing that it hopes to end up with nearly $890M from a public offering of 100M shares at an expected price of about $9.25 a share. The stock will trade at NASDAQ under the symbol ZNGA. The cash will be used for “general corporate purposes” which could include acquisitions. The company says it also plans to contribute a some of the net proceeds to charitable causes through its philanthropic initiative, Zynga.org. Today’s announcement follows its disclosure this past summer that it planned to go public — seizing on Wall Street’s infatuation with tech companies. Investors have become a little more skeptical about the category, though: For example, Pandora Media is down about 40% since it went public in June. LinkedIn is down 28% since May. And Groupon lost 27% of its market value after it hit the market early last month. Zynga investors also will have no power over the company. The Class A shares that the public will buy have one vote per share. But insiders including founder and CEO Mark Pincus control the Class B and Class C stock that account for 98.2% of all the voting shares. Zynga has close ties to DreamWorks Animation; Jeffrey Katzenberg is a member of its board. The studio also was an early ad sponsor. For example, players building cities in the game CityVille could add drive-in movie theaters that played Kung Fu Panda 2. Zynga says that it’s “the world’s leading social game developer” with 227M average monthly active users in 175 countries. In the nine months ending in September it had a net profit of $30.7M, down 35.5% from the same period last year, on revenues of $828.9M, up 106.3%.