Warren Buffett reveals he stepped down after finally feeling his age

Buffett plans to step down as CEO in December and make way for Greg Abel, though he said he intends to keep working

- Karen Langley

Warren Buffett can't put his finger on exactly when he decided to hand over the reins of Berkshire Hathaway to Greg Abel.

But in recent years Buffett observed just how much energy his appointed successor brought to each working day. And how his own days had slowed. The two men were operating at different speeds—increasingly so.

"There was no magic moment," Buffett, now 94, said in an interview with The Wall Street Journal. "How do you know the day that you become old?"

Berkshire shareholders and onlookers have long wondered how anyone could replace Buffett, for decades a towering figure in American business and finance. But as he passed his 90th birthday, Buffett began to experience something most people come to accept much earlier in life: his age.

"I didn't really start getting old, for some strange reason, until I was about 90," he said by phone from his office in Omaha, Neb. "But when you start getting old, it does become—it's irreversible."

He began to lose his balance, occasionally, and sometimes had trouble recalling a person's name. Suddenly, the newspapers he read looked like they were printed with too little ink.

In the past year, those thoughts and feelings cohered into a decision. On May 3, at the Berkshire annual meeting, Buffett stunned the investing world when he revealed in the final minutes of his question-and-answer session his plan to step down as CEO in December and make way for Abel.

Buffett will continue to serve as chairman of Berkshire's board and has set no timeline for staying in that role.