Did Facebook Just Spill the Beans on Zynga’s Fourth Quarter?

Zynga isn’t reporting its fourth-quarter results for another two weeks, but some quick math, based on Facebook’s numbers yesterday, show that it likely did fairly well.

Because of that, Zynga’s stock is soaring today, trading up 16.5 percent, or $1.75 a share, at $12.35, to easily beat its 52-week high of $11.50.

Up until today, Zynga’s stock had struggled to stay at its IPO price of $10 a share.

Baird Equity Research analyst Colin Sebastian tried to do some backward math based on Facebook’s disclosure yesterday that 12 percent of its revenue was coming from the social games company.

Based on that alone, we know that Zynga accounted for roughly $450 million of Facebook’s $3.7 billion revenue in 2011.

But Sebastian took it a step further and estimated that, based on Facebook’s 20 percent jump in payment revenue during the fourth quarter, Zynga’s net bookings likely totaled $315 million in Q4, versus the $300 million he was previously forecasting.

He maintained the company’s “outperform” rating on the stock, and a $12 price target.

Here’s how he did the math:

We estimate that 12% of Facebook revenues came from Zynga in Q4, which implies roughly $135 million in Zynga-related revenues. We assume 75-80% of this amount is fees related to virtual good sales, with the remainder coming from advertising. Adjusting this amount for the 30% toll, we estimate implied net bookings to Zynga of nearly $250 million from virtual good transactions on Facebook. We estimate that Zynga also generated roughly $65 million in Facebook advertising bookings and transactions on other platforms (e.g., iOs, Android), which would suggest total net bookings of $315 million vs. our estimate of $300 million. Again, this a rough estimate and a directional indicator based on Facebook filings.