Since touching a nine-year low in September, shares of Research in Motion have been on a tear, up over 120 percent just ahead of the launch of its new BlackBerry.
Yet just as the stock continues to climb, so has interest in short positions, or investors piling on bets to sell.
At the end of last month, short interest reached a peak of 113.7 million shares, the highest level since January 2004. That would put short interest for the stock at about 22 percent.