4. Bank of America

Though it might seem a bit of a surprise to many investors, Berkshire Hathaway made $5 billion worth of preferred-share investment in Bank of America last year. This deal turned out to be quite a win-win situation for Berkshire Hathaway as it garnered a 6 percent yield and an additional 10 year warrants to buy 700 million shares of the Bank at $7.14 each. Buffett backs his investment by saying that despite previous management mishaps, CEO Brian Moynihan “has made excellent progress in cleaning these up” and that “he is nurturing a huge and attractive underlying business that will endure long after today's problems are forgotten.”