Warren Buffett, CEO of Berkshire Hathaway Inc, (2nd L) plays bridge with Bill Gates, founder of Microsoft as part of the company annual meeting weekend in Omaha, Nebraska U.S. May 6, 2018.

Shareholder Faye Meriwether fans herself with a fan with an image of Warren Buffett at the Berkshire Hathaway Inc annual meeting, the largest in corporate America, in its hometown of Omaha, Nebraska, U.S., May 4, 2018.

Warren Buffett, CEO of Berkshire Hathaway Inc, takes a drink of Cherry Coke while playing bridge as part of the company annual meeting weekend in Omaha, Nebraska U.S. May 6, 2018.

A worker holds a commemorative Heinz ketchup at the Heinz exhibit at the Berkshire Hathaway Inc annual meeting, the largest in corporate America, in its hometown of Omaha, Nebraska, U.S., May 4, 2018. REUTERS/Rick Wilking

Warren Buffett, CEO of Berkshire Hathaway Inc, walks through the exhibit hall at the company's annual meeting in Omaha, Nebraska, U.S., May 5, 2018.

Warren Buffett, CEO of Berkshire Hathaway Inc, gestures while playing bridge as part of the company annual meeting weekend in Omaha, Nebraska U.S. May 6, 2018.

A Berkshire Hathaway shareholder hugs a Kool-Aid Man character in the exhibit hall at the company's annual meeting in Omaha, Nebraska, U.S., May 5, 2018.

Thousands of shareholders wait for the Berkshire Hathaway Inc annual meeting to begin in Omaha, Nebraska, U.S., May 5, 2018.

A woman takes a nap while waiting with the crowd for Warren Buffett, CEO of Berkshire Hathaway Inc, to come to the table tennis area as part of the company annual meeting weekend in Omaha, Nebraska U.S. May 6, 2018.

A young girl holding a doll of Warren Buffett, CEO of Berkshire Hathaway Inc, watches Buffett walk through the exhibit hall at the company's annual meeting in Omaha, Nebraska, U.S., May 5, 2018.

A shareholder look over commemorative Heinz ketchup and mustard at the Heinz exhibit at the Berkshire Hathaway Inc annual meeting, the largest in corporate America, in its hometown of Omaha, Nebraska, U.S., May 4, 2018.

Shareholders Deborah Kiel (L) and Laura Flynn react to a Warren Buffett fan at the Berkshire Hathaway Inc annual meeting, the largest in corporate America, in its hometown of Omaha, Nebraska, U.S., May 4, 2018.

Warren Buffett, CEO of Berkshire Hathaway Inc, talks to a reporter in the exhibit hall at the company's annual meeting in Omaha, Nebraska, U.S., May 5, 2018.