Warren Buffett's company owns these stocks, and they could be great additions to your portfolio.Berkshire Hathaway CEO Warren Buffett helped turn the investment conglomerate into one of the world's most valuable companies. With a market capitalization of approximately $1.08 trillion as of this writing, Berkshire ranks as the world's 11th-biggest business (at the time of this writing). Given Berkshire's incredible success, it's little wonder that many investors pay close attention to the company's stock hold ...