Stan Druckenmiller is now the second major hedge fund manager this week to oppose Warren Buffett over a stock. He said today that he’s actually shorting International Business Machines Corp. (NYSE:IBM), which happens to be one of Buffett’s two largest position, according to a recent Bloomberg interview conducted at The Robin Hood Conference. Buffett’s stake in IBM is estimated to be worth as much as $13 billion. Incidentally, one of Buffett’s other largest positions, Exxon Mobil Corporation (NYSE:XOM), is being shorted by Jim Chanos. Twitter posts from various users and some analysts suggest that Druckenmiller’s comments about International Business Machines...