 Speaking at the Value Investing Congress in New York City on October 17, 2011, Einhorn publicly announced his short position in Green Mountain Coffee Roasters stock.Prior to that date, the company's share price had increased more than tenfold since March 2009, the third-biggest gain in the Standard & Poor's Midcap 400 Index.In his presentation Einhorn opined that the market for Green Mountain's new Keurig single-cup coffee brewer was "limited," and that the K-Cup coffee pods for the machine presented a "looming patent issue" for the company.