Warren Buffett, chairman of Berkshire Hathaway Inc., center, laughs with Bill Gates, chairman and founder of Microsoft Corp. and a Berkshire Hathaway Inc. director, left, as they play bridge during a shareholder event on the sidelines of the Berkshire Hathaway Inc. annual shareholders meeting in Omaha, Nebraska, U.S., on Sunday, May 3, 2015. More than 40,000 people were expected to attend yesterday's Berkshire Hathaway annual meeting, which marks Warren Buffett's 50th year running the company. Photographer: Daniel Acker/Bloomberg via Getty Images