Billionaire Warren Buffett will remain chairman of Berkshire Hathaway after Greg Abel takes over as CEO at the start of the new year

Warren Buffett shook the investment world on Saturday with four words: "The time has arrived." At 94, Buffett's pronouncement that he step back from CEO duties — which he will recommend to the board in a meeting set for Sunday — is less a shock than a matter of necessity.

"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.