Warren Buffett just released his widely anticipated annual letter to Berkshire Hathaway shareholders. As usual, it should be required reading for all investors.

Warren Buffett's latest letter to Berkshire Hathaway shareholders offered reflections on mistakes at the company, its growing cash pile, and outlined a slightly revamped annual meeting set for May.

Warren Buffett is celebrating the successes of Berkshire Hathaway’s companies last year and in the 60 years since he took over a struggling New England textile company and began converting it into a massive conglomerate.