Good morning. CFO turnover continues in the Fortune 500, and now it’s reached one of the most watched companies in American business: Berkshire Hathaway.
Marc Hamburg, the longtime SVP and CFO at Berkshire, will retire on June 1, 2027, after 40 years of service, the massive American conglomerate and holding company announced on Monday. Hamburg, who joined Berkshire in 1987, will be succeeded by Charles C. Chang, who was appointed SVP and CFO effective June 1, 2026. Chang is currently SVP, CFO, and director of Berkshire Hathaway Energy. He will work with Hamburg during a transition period.
These leadership changes come as legendary investor Warren Buffett prepares to step down as CEO at the end of the year. Berkshire announced in May 2025 that Buffett will be succeeded by Greg Abel, vice chairman of its non-insurance operations. Buffett will remain with the company as chairman of the board after the transition.
Having worked with Hamburg for decades, Buffett praised him in a statement: “Marc has been indispensable to Berkshire and to me. His integrity and judgment are priceless. He has done more for this company than many of our shareholders will ever know. His impact has been extraordinary.”
Hamburg has maintained a low profile while leading the finance organization of one of the most successful and renowned companies in the Fortune 500. Berkshire consistently ranks in the top 10 on the list.
Abel, whose tenure as CEO will soon begin, joined Buffett’s ecosystem a quarter-century ago when Berkshire entered the energy field. As CEO of Berkshire Hathaway Energy starting in 2008, the business grew significantly to include a vast portfolio of utilities, pipelines, natural gas plants, and wind and solar farms, Fortune reported. Since 2018, Abel has served as vice chairman of Berkshire’s non-insurance operations.
Chang, 56, joined Berkshire Hathaway Energy in October 2024; now he will join Abel as his strategic partner in leading the entire firm. Chang was previously a partner in PricewaterhouseCoopers’s energy practice, working with large multinational energy companies. He has 34 years of experience in accounting, U.S. Securities and Exchange Commission reporting, mergers and acquisitions, and sustainability.
Analysts expect more turnover ahead
Meyer Shields, managing director at Keefe, Bruyette & Woods, an investment bank and broker-dealer, wrote in a note on Monday that the primary takeaway from Berkshire’s announced leadership changes is that “no matter how desirable consistency is—change is inevitable when a 50-year-plus CEO steps back.”
He added, “Implying no disrespect to incoming president and CEO Greg Abel, we expect more turnover in coming months, since the cachet of working for Mr. Buffett’s successor is not (at least yet) the same as working for Mr. Buffett himself.” Shields expects Berkshire’s “weak disclosure” to prove inadequate to investors who were comfortable relying on Buffett in the past.
I asked Shawn Cole, president and co-founder of the executive search firm Cowen Partners, why he thinks Berkshire chose Chang as the next CFO.
Because Chang’s background is rooted in public accounting as a PwC partner, followed by roles focused on reporting and compliance, his experience “signals clean audits, rigor, and financial discipline,” Cole said.
“Chang’s strength is managing a very large asset and equity base and continuing heavy capital investment, while keeping a highly regulated, multi-jurisdictional portfolio clean on reporting and fully compliant with SOX requirements,” Cole explained. “Paired with Abel’s operating experience, that is more of a disciplined refinement than a strategic overhaul—which is exactly what a company this successful calls for.”
Berkshire announced additional leadership changes on Monday. In insurance operations, Nancy Pierce was promoted from COO to CEO of GEICO, effective immediately. Pierce succeeds Todd Combs, who will conclude his tenure at Berkshire and join JPMorgan Chase, where he has served as a director on its board since 2016. Adam Johnson, currently CEO of Berkshire unit NetJets, was appointed president of Berkshire’s consumer products, services, and retailing businesses. Michael O’Sullivan has been appointed SVP and general counsel.
“There has been a lot of turnover leading up to Abel’s start, frankly,” Cole said. “And while Warren Buffett has executed a CEO succession plan many of his peers should study, the missed opportunity was not locking key leaders into retention agreements or incentives to stay through the transition. What we’re seeing now is a larger changing of the guard—planned or not.”
Sheryl Estrada
sheryl.estrada@fortune.com
Leaderboard
Heather Planishek was appointed CFO of Lambda, an AI cloud infrastructure provider that specializes in high-performance GPU computing. Planishek most recently served as chief operating and financial officer at Tines, an intelligent workflow platform. She previously served as chief accounting officer at Palantir Technologies Inc. Earlier in her career, Planishek held key leadership roles at Hewlett-Packard Enterprise and Ernst & Young. Planishek joined Lambda’s board of directors in July of this year, and as part of the transition, will step down from her board position.
Matthew M. Pullins was appointed EVP, CFO and treasurer of The Federal Agricultural Mortgage Corporation (Farmer Mac; NYSE: AGM and AGM.A), effective Dec. 11. 2025. Pullins brings more than two decades of experience. He most recently served as SVP and CFO of capital markets at PNC Financial Services Group, Inc. Earlier in his career, Pullins served as CFO of PNC's institutional asset management division.
Big Deal
OpenAI has released its first "State of Enterprise AI" report, which explains how companies are adopting AI, where they’re seeing value, and what separates early leaders from the pack, CFO Sarah Friar wrote in a LinkedIn post on Monday.
"The picture that emerges is clear: enterprise AI adoption is accelerating not just in breadth, but in depth, as businesses use it for increasingly sophisticated tasks," Friar wrote.
According to the report, ChatGPT now serves more than 800 million users every week, which is accelerating the pace at which AI is being brought into work and professional settings. One key finding is 75% of users report being able to complete new tasks they previously could not perform. The findings are based on a survey of 9,000 workers across almost 100 enterprises.
Going deeper
"A divided Fed meets today and Wall Street is listening for 4 key words from Powell: ‘In a good place’" is a Fortune report by Jim Edwards.
Edwards writes: "The chances of the Fed delivering another interest rate cut tomorrow are 90%, according to bets tracked by the CME FedWatch Fed funds futures index. But Wall Street has already priced that in. The S&P 500 ticked down 0.35% yesterday but remained near its all-time high, and futures were flat this morning. In fact, traders have already moved on from the decision itself, which they regard as a done deal, even though the Federal Open Markets Committee is sharply divided over whether a cut should actually take place." You can read the complete report here.
Overheard
"Some people worry that AI-driven hiring slowdowns are disproportionately impacting younger workers. Yet the greater opportunity lies in a new generation of AI-native professionals entering the workforce equipped for how technology is transforming roles, teams, and leadership."
—Justin Hotard, Nokia’s president and CEO, writes in a Fortune opinion piece.
