Playing cards bearing an image of Warren Buffett, chairman of Berkshire Hathaway Inc., right, and Charlie Munger, vice chairman of Berkshire, are displayed during the Berkshire Hathaway annual shareholders meeting in Omaha, Nebraska, U.S., on Saturday, May 5, 2012. Berkshire Hathaway's first-quarter profit doubled as insurance units and derivative bets posted better results, the company said yesterday. Photographer: Daniel Acker/Bloomberg via Getty Images