Seismic at the top of Berkshire Hathaway management before Warren Buffett's retirement. The lieutenant of the “Oracle of Omaha” is leaving for another huge US company

Berkshire Hathaway announced a management shakeup on Monday, weeks before Warren Buffett handed over control to Greg Abel, with a key executive leaving for JPMorgan Chase to support the bank's US investment project. Berkshire has announced other changes at the level of the management of the financial conglomerate, writes Reuters.

Marc Hamburg, the company's longtime chief financial officer, who joined the team in 1987, will retire on June 1, 2027, after four decades at the conglomerate, Berkshire Hathaway said.

Investment manager Todd Combs will leave to lead the strategic investment group of JPMorgan's new security and resilience initiative, according to the US bank.

Charles Chang, chief financial officer of Berkshire Hathaway Energy, will succeed Hamburg next year.

“Marc has been indispensable to Berkshire and to me. His integrity and judgment are invaluable,” Buffett said in a statement.

Abel's transition to CEO on Jan. 1 ends Buffett's extraordinary six decades at the helm of Berkshire Hathaway, during which Buffett became a household name, a multimillionaire, and the image of an American success story.

“Abel is positioning trusted lieutenants and new talent to balance continuity with modernization at Berkshire; making changes under Buffett's watch as chairman allows him to make his mark while showing shareholders that the 'Oracle of Omaha' agrees,” explained Michael Ashley Schulman, chief investment officer at Running Point Capital.

Investor Warren Buffett, 95, is known for his market instincts and his long-held nickname – “The Oracle of Omaha”.

Combs and another Berkshire investment manager, Ted Weschler, were once favorites to take over the company's stock portfolio after helping Buffett invest in stocks, but the CEO has said in recent years that Abel can handle it.

The appointments underscore Berkshire's tradition of selecting leaders who support the financial conglomerate's culture, demonstrate strong business acumen and support its distinctive operating model, the company said, adding that it remains well-positioned for the future.

Berkshire Hathaway also announced changes to its insurance and non-insurance operations and named Michael O'Sullivan as general counsel, marking the creation of a new position within the company.

However, many of the non-insurance businesses – including industrial products, building products, BNSF, Berkshire Hathaway Energy, Pilot and McLane – will remain under Abel's direct supervision once he takes over as CEO.

Combs will lead JPMorgan's new project

At JPMorgan, Combs will work with the firm's Commercial & Investment Bank and Asset & Wealth Management divisions to pursue opportunities covering mid-market clients and large companies in the defense, aerospace, healthcare and energy industries, the US bank said.

Earlier this year, the Wall Street giant launched the Security and Resiliency Initiative (SRI), a $1.5 trillion, ten-year plan to support industries deemed vital to U.S. security and economic resilience.

As part of the program, the bank said it will allocate up to $10 billion in direct equity and venture capital investments to help select U.S. companies expand their growth, drive innovation and accelerate strategic manufacturing.

Separately, JPMorgan Chase announced that it has established an external advisory board of public and private sector leaders to help coordinate the bank's Security and Resiliency initiative.

The board will be chaired by Jamie Dimon, CEO of JPMorgan, and will include members such as Jeff Bezos, founder of Amazon, Michael Dell, CEO of Dell Technologies, and Condoleezza Rice, former US Secretary of State. Combs will also serve on this advisory board.

“JPMorgan has brought together a group of top government, defense, technology and industry experts for its SRI advisory board, who should have a good understanding of the interaction between Washington, DC politics, government contractors and corporate America,” Michael Ashley Schulman added.

Combs, who previously served on JPMorgan's board, will join the bank in January and report directly to Dimon.

Combs was recruited by Buffett from a small hedge fund to join Berkshire in 2010.

Along with Ted Weschler, Combs helped manage Berkshire's massive investment portfolio, particularly its successful stake in tech giant Apple, according to Axios.