What happened

Mobile video game company Zynga (ZNGA) saw its stock price plunge 12.4% in August, according to S&P Global Market Intelligence. The maker of Words with Friends and FarmVille trailed the S&P 500, which was up 2.9% in August.

Zynga's stock price is down about 10% year to date as of Sept. 3, trading at just under $9 per share. It is trailing the S&P 500, which is up 21% as of Sept. 3.

A woman lying on a bed playing a mobile video game.

Image source: Getty Images.

So what

Zynga is one of the premier providers of mobile video games, the kind you play on your phone or tablet. In addition to the above-mentioned games, it also offers Zynga Poker, Toon Blast, Toy Blast, Harry Potter: Puzzles & Spells, Merge Dragons! and Merge Magic! to name a few. It makes money though purchases related to its games and through advertising.

The plunge in August may be a head scratcher on its face, as Zynga reported a 59% increase in revenue to $750 million and a 37% increase in bookings, which factors in deferred revenue. Net income was $28 million, up from a $23 million net loss in Q1 and a $150 million net loss a year ago.

While those numbers look good, the drop in stock price may have been because Zynga missed the consensus estimate of $716 million for bookings -- which is the primary performance metric the company and analysts use.

Now what

The miss on bookings is likely caused by there being slightly fewer users than expected due to economies opening back up over the summer and Apple's recent mobile app privacy changes, explained CEO Frank Gibeau on the second-quarter earnings call. The new Apple privacy changes created some "choppiness," particularly with new customer acquisition, but Gibeau said it's temporary, as user acquisition is already recovering.

Overall, Zynga had a record number of daily active users, 41 million in the quarter, up 87% year over year, and monthly active users, 205 million, up 194%. In addition, it acquired the popular golf game Golf Rival, which should provide a boost.