As CEO and primary shareholder of Berkshire Hathaway (BRK), Warren Buffett, the world's most famous investor, has developed a well-known reputation of buying big stakes in companies he believes in. When Buffett buys shares of a company for BRK, the markets translate his moves as a vote of confidence for a firm's continued success. Although Berkshire Hathaway's holdings change, the company's most recent SEC filings* reveal where the Oracle of Omaha is most heavily invested. Here are the 15 publicly traded stocks, by value, that are the biggest holdings of Berkshire Hathaway.