Warren Buffett’s Berkshire Hathaway (NYSE: BRK-A) (NYSE: BRK-B) made a nearly $11 billion bet on tech giant International Business Machines (NYSE: IBM) in 2011. The move seemed out of character for Buffett, who typically shuns tech stocks for being well outside his circle of competence. But IBM’s entrenched status in many industries gave it competitive advantages that Buffett couldn’t resist.