"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.

Warren Buffett shook the investment world on Saturday with four words: "The time has arrived." At 94, Buffett's pronouncement that he will step back from CEO duties and hand the reins to Abel — which the company made official with a unanimous vote on Sunday — is less a shock than a matter of necessity.

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.