In 2006, when Giving Pledge was just a glimmer, Warren Buffett tied his fortune to the Gates Foundation; here are 4 reasons why that plan is obsolete.

"Warren Buffett piled up the world's third biggest fortune, $66 billion, by making smart bets. His philanthropy is another story: Eight years ago, Buffett pledged the bulk of his fortune to the Bill & Melinda Gates Foundation. And while that bet seemed pretty smart at the time, it's turned out to be a mistake. Here are four reasons why Warren should back out of his pledge to Gates." -- David Callahan, Inside Philanthropy

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