Activision BlizzardActivision Blizzard ( ATVI) is having a tough year -- shares of the $12 billion video game maker have fallen around 8% in the last 12 months, underperforming the S&P 500 by 22.42%. But the technical setup in this stock points to even more toxic price action in 2013. That's because Activision Blizzard has been stuck in a volatile downtrending channel for the better part of the last year, bouncing in between trendline resistance to the upside and trendline support below shares. The strength of that trendline resistance level is significant -- it's the price above which there's a consistent glut of selling pressure for shares, so it provides an ideal selling point for investors trying to squeeze the most out of this stock (or for short sellers trying to do the same). Until this stock can manage to take out those sellers above resistance, I'd strongly recommend staying away from shares of this stock. If it cant catch a bid above resistance, you don't want to be a buyer.