As badly as short sellers want to hate on Green Mountain Coffee Roasters ( GMCR), betting against the multiyear rally in this $12.7 billion beverage stock has been about as wise as eating from a box with a skull and crossbones on it. And as a bull market continues to lift all ships, Green Mountain's ship is going to keep floating above the others. >>5 Earnings Short-Squeeze Plays Green Mountain owns Keurig, the brand of beverage brewers that use self-contained K-Cups to make coffee, teas, and other drinks. While Keurig's "fad" status has certainly helped tip the deck against GMCR, the fact remains that the firm has done most of the hard work in getting Keurig machines accepted by consumers. With brewers essentially ubiquitous at this point, the firm is able to make money on its cash cow: the K-Cups. Keurig's individual-serving cups have big margins and a big installed base. With huge convenience and the relatively large sunk cost that consumers have put into their Keurig machines, it's a sticky business with big switching costs. Consumers who buy a Keurig are much less likely to spend the money on a competing brand of proprietary coffee pods. I've said before that GMCR is far from cheap right now. But its momentum trajectory is showing few signs of fizzling out, especially as direct competitors such as Starbucks ( SBUX) continue to sell K-Cups of their own. Don't bet against GMCR in September - buy this Rocket Stock instead.