Buffett, one of the world’s richest people and most accomplished investors, took control of Berkshire Hathaway in 1965 when it was a textiles manufacturer. He turned the company into a conglomerate by finding other businesses and stocks to buy that were selling for less than they were worth.

"You're losing one of the most esteemed investors one could argue of all time," a source said of investors' reaction to Buffett's plan to step down.