Activision Blizzard, Inc. (ATVI - 12.26) saw an upswing in bullish options activity on Friday, as north of 7,300 calls crossed the tape, more than doubling the equity's average daily volume. More than 4,200 of these calls were exchanged at the near-the-money May 13 strike -- most of them at the ask price, indicating they were purchased. Open interest at this strike rose by 2,847 contracts over the weekend, pointing to an influx of new positions. This option now holds peak call open interest of 17,099 contracts. In order for traders to make a profit from these bought-to-open calls, the stock must ascend above $13 by front-month expiration.

This preference for calls over puts is further evidenced by ATVI's 10-day International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX) call/put volume ratio, which stands at 3.50. In other words, traders have bought to open 3.5 calls for every put during the last two weeks.

Meanwhile, although short interest on the video-game titan declined by more than 8% during the past month, these shorted shares still make up over 6% of ATVI's available float. This raises the possibility that some of the recent call volume is the work of short sellers looking to hedge their bearish bets.

Technically speaking, ATVI has advanced by around 8% on a year-over-year basis. However, the stock has had a bit of a roller-coaster ride on the charts lately, and is currently trading beneath its 10-day moving average -- a trendline that has alternately served as both support and resistance since the beginning of the year.

ATVI is scheduled to reveal its first-quarter earnings after Wednesday's close, and has bested analysts' bottom-line estimates in each of the past four quarters. In the first hour of the session, however, the equity is down about 0.8% to hover at $12.26.