Warren Buffett's move to step down Friday as Berkshire Hathaway's chairman ends an extraordinary run that began when he took control of a struggling textile company in 1965 and turned it into the world's largest conglomerate with a $1.1 trillion market value.

Buffett, who turned 96 on Aug. 30, is succeeded by his son, Howard Buffett, 71, and is now chairman emeritus in what Berkshire called a "longstanding succession plan." In January, Greg Abel succeeded him as CEO.

Buffett's decision raises some questions about Berkshire's future direction. Perhaps most important is management of Berkshire's equity portfolio, now totaling over $350 billion.

Abel will likely wield more power, although Buffett will remain the wise, steady voice that he has been for the past nine months.

As chairman, Buffett came into the office every day and consulted with Abel on key business and investment decisions, such as Buffett's move to purchase of Alphabet shares-a stake now worth about $35 billion.

In July, Buffett told CNBC about Abel: "I am not doing anything that he doesn't approve of. He's not doing anything I don't approve of. We talk all the time."

Buffett's role as partner and counselor is no surprise. His understanding of markets and business is keen-perhaps unparalleled-and he is Berkshire's control shareholder with a 13% economic stake, and 30% voting control, worth over $140 billion.

Still, the Abel era at Berkshire is getting nearer.

The company didn't cite any health issues, but Buffett has dealt with problems common with people his age-deteriorating eyesight and a broken a leg. He disclosed both health matters to CNBC this year.

Buffett's continued involvement as chairman in Berkshire's equity portfolio was evident first and foremost with the Alphabet purchase, which has grown to about $35 billion, making it the company's third largest equity holding along with Coca-Cola behind Apple and American Express.

Abel has no formal portfolio management experience and doesn't appear to have made any significant moves with the Berkshire equity holdings other than to sell about $15 billion of stocks that were managed by former manager Todd Combs, who left for an investment role at JPMorgan Chase in December.

Berkshire investment manager Ted Weschler, 65, has responsibility for about 6% of the portfolio. Many Berkshire watchers thought he would get considerably more authority as part of the CEO transition to Abel, but he received only a small increase in the amount of stocks that he oversees.

Will Berkshire hire additional investment minds? Will Weschler get more authority over the equity portfolio? And will Buffett, who loves the markets, still make equity buys and sells?

It's unclear now.

Abel appears to be de-emphasizing the importance of the equity portfolio as a creator of value for Berkshire. He spends his time on what he does best-operations-and has his hands full given Berkshire's dozens of operating units.

The CEO told shareholders in his initial shareholder letter that a large part of the equity portfolio likely wouldn't change, including Coke, Apple, and Moody's.

In Friday's announcement, Buffett said the "timing is right to complete the transition" in part because of what he termed the great job that Abel has done as CEO.

"My expectations for him were sky high from the start, and he has exceeded them. He has taken hold of the Chief Executive Officer job in every respect," Buffett said.

"Recently, I celebrated my 96th birthday with family and friends, including one of my great-grandchildren, who had just turned one. He's moving a bit faster than I am these days," Buffett wrote.

"I have served Berkshire since 1965. Sixty-plus years in, I still have the best job in the world. That is not something many people my age can say, and I have never felt better about what comes next."

Buffett has written in the past that he wanted his son, Howard, an Illinois farmer who is active in philanthropy, to succeed him as chairman.

Buffett has stated that Howard Buffett's role would be to guard Berkshire's culture and values and he reiterated that point in his remarks in the letter.

"Think of Howard as a policy the shareholders own and hope never to claim against. Howard cares deeply about Berkshire, as do all of our Directors. No company has been or will be more shareholder-minded than Berkshire."

Buffett's move drew praise from one shareholder.

"While the share price performance has been frustrating this year despite positive trends in the underlying business, the announcement that Warren Buffett will shift to chairman emeritus is the latest example in the textbook of good governance at Berkshire," said Chris Davis, a co-founder and portfolio manager at Hudson Valley Partners.

"I can't imagine it was an easy decision for Warren Buffett on a personal level, and I hope it gives anyone close to retirement the confidence to pass the baton," added Davis, who isn't related to Berkshire director Chris Davis..

Berkshire's Class A stock ended Thursday at $763,935 and the B shares at $509.20, both down 2% in the session. Both classes of stock are up about 1% this year, way behind the S&P 500's 12% return.

Buffett sounded confident about Berkshire's future in the announcement:

"Serving as your Chairman has been the privilege of a lifetime, and I have never taken your trust for granted. Father Time always wins. He has, however, been generous with me. He has given me the opportunity to see Berkshire reach a point where I am more confident than ever about what lies ahead," he said.

"The company is in excellent hands, and I look forward to remaining a shareholder alongside you."