Berkshire Hathaway Inc. (NYSE: BRK-A) has released its annual letter for 2016, and 24/7 Wall St. has already broken out many of the top trends and takeaways from that report. Covered here are the most profitable positions in the Berkshire Hathaway portfolio. When Warren Buffett speaks (or invests), people tend to listen. Having attained the status of the world's wealthiest person on paper makes people care. Buffett is also considered to be the greatest investor of the modern era.