After 60 years in the role he essentially bought with what he called the "dumbest" investment of his life, Wednesday marked Warren Buffett's final day as Chief Executive Officer of Berkshire Hathaway.

His core strategy involved using premiums from insurance operations—"float"—to make exceptional stock investments and facilitate the acquisition of entire companies. This approach transformed a struggling textile mill into a trillion-dollar commercial empire and propelled Buffett to become one of the world's wealthiest individuals, with a net worth exceeding $150 billion.

He has already donated shares currently valued at $208 billion and has instructed his children to eventually give away nearly all of his remaining fortune.

This is not a complete retirement. The 95-year-old will continue as Chairman of the board and still plans to visit the company's Omaha headquarters as frequently as ever.

However, he stated he will "stay silent... sort of," ceding all decision-making authority to the new CEO, Greg Abel. Abel has served as Vice Chairman of non-insurance operations since 2018. He first joined Berkshire in 2000 when the company acquired a controlling stake in MidAmerican Energy, where he was President at the time.

Nonetheless, when Buffett announced his plan to step down by year-end at the annual meeting in May, he expressed hope that he could still be helpful, particularly "if we hit a real opportunity period or anything."

CNBC's long-time Berkshire/Buffett reporter Becky Quick noted on Wednesday's "Squawk Box" that Abel has been "very much" running the non-insurance companies "for years" and has done a "fantastic job" ensuring smooth operations and handling many issues Buffett himself preferred to avoid.

She suggested that having Buffett and his 30% voting control as a "firewall" would help Abel counter anyone wanting to criticize him by saying, "You're not Warren Buffett, this isn't your company."

In fact, Abel has already begun imprinting his own style on how he manages Berkshire's wholly-owned subsidiaries. He involves himself more in the specifics of subsidiary management compared to Buffett's famous hands-off, decentralized approach.

At the 1999 annual meeting, Buffett and Charlie Munger stated that their "policy of non-intervention has great value, at least with the kind of managers and businesses we attract." "People not only have more time for productive things, but I think they may really appreciate being able to run their own show."

Twenty-four years later, Buffett remarked, "Our managers like autonomy, but they also get lonely... I give them autonomy, and Greg gives them autonomy and companionship, and the discipline he gets from the managers... is a little greater than what I could get."

Earlier this month, Berkshire announced a new layer of management, appointing the CEO of its NetJets subsidiary to "support the excellent CEOs of our 32 consumer products, service, and retail businesses and preserve the Berkshire culture and values."

However, while changes are beginning at Berkshire, they will not constitute an overnight transformation.

As shareholder Ann Winblad told CNBC's "Squawk Box" on Wednesday, while the company will "operate differently" under the new CEO, its strategy will not see a "fundamental change."

Andrew Bary of Barron's wrote that Buffett's continued presence at the company "likely means some big items—such as a potential dividend (which Buffett has long opposed), stock buybacks, and the deployment of Berkshire's more than $350 billion cash hoard—could be in limbo for some time, perhaps until after Buffett dies."

From a very long-term perspective, however, Berkshire will inevitably become more like other companies. Those firms lack Buffett's stellar track record to shield management from pressure by impatient investors, who would likely push the company to abandon Buffett's principle of "waiting for the right pitch" and resist the typical executive impulse to constantly "do something" to justify their roles.

**Berkshire Stock Underperforms S&P 500 in Buffett's Final Year**

Another significant unknown is how Berkshire's stock will perform without Buffett as CEO.

This year, the company's shares underperformed the benchmark S&P 500 index, as investors reacted negatively to Buffett's early May announcement that he would hand over the role to Abel by year-end.

The day before Buffett's unexpected announcement, Berkshire's Class A shares closed at a record $809,350. The price subsequently declined, hitting a yearly closing low of $692,600 on August 4th, a drop of 14.4%. The stock partially recovered, closing the year at $754,800, up nearly 10.9% for 2025. The more widely held Class B shares followed an almost identical trajectory.

Meanwhile, the S&P 500 staged a strong recovery this year, finishing with a 16.4% gain after a Trump tariff announcement pushed markets toward bear territory in April.

Consequently, Berkshire's Class B shares, which had been leading the S&P 500 by 22.4 percentage points in May, ended the year trailing by 5.5 percentage points.

Including dividends, the S&P 500's total return for the year was 17.9%, widening Berkshire's relative underperformance to a 7 percentage point deficit, a stark contrast to its narrow 0.5 percentage point victory in 2024.

Since Buffett took control in 1965, fortunate investors in Berkshire have realized a return of approximately 6,100,000%, vastly outperforming the S&P 500's roughly 46,000% return (including dividends).