Warren Buffett, Chairman of Berkshire Hathaway Inc.

Warren Buffett, Chairman of Berkshire Hathaway Inc.

Warren Buffett, chairman of Berkshire Hathaway Inc., said David Sokol, who resigned from Berkshire Hathaway Inc. last month, broke the company’s ethics rules when he bought stock in a company that he recommended as a takeover target. Daniel Acker/Bloomberg