Game On! Zynga Starts Slowly On First Day of Trading.

Zynga has opened its stock-market debut at $11 a share, a small increase over its initial pricing from last night.

Late last night, the San Francisco social games company officially priced its shares at $10 apiece. It was hoping to sell up to 100 million shares at $8.50 to $10 apiece. At $10, Zynga was able to raise $1 billion in capital.

But investors aren’t going nuts for the stock. At one point this morning ZNGA shares were trading below their initial price at $9.50 a share.

That’s certainly not the kind of pop companies look for. On the bright side, perhaps the small (or non-existent) bump will make the company less likely to suffer the double-digit declines that recent Web IPOS like LinkedIn, Pandora, and Demand Media have all experienced this year.

At this price, the company is valued at $7.6 billion. That makes CEO Mark Pincus’s stake worth $1.2 billion.