Top 10 US Family Offices of Billionaire Dynasties

Koch Industries operates as an effective family office for Charles and David Koch’s descendants, generating $120 billion+ in revenues as the second-largest private company in America. Its portfolio spans refining, chemicals, consumer brands (Georgia-Pacific, Brawny), and financial services. Since 2000, the family has deployed over $3 billion into political and policy advocacy. In 2025–2026, it expanded into renewable energy to diversify beyond fossil fuels.

MSD Partners is the investment firm that grew out of Michael Dell's family office, MSD Capital, and manages capital for the Dell family alongside outside investors across real estate, public equities, private credit and direct investments. In 2023 it combined with Byron Trott's BDT & Company to form BDT & MSD Partners.

Soros Fund Management, the family office of legendary investor George Soros, manages approximately $25 billion in endowment assets for the Open Society Foundations after converting from a hedge fund in 2011. The firm pioneered macro investing strategies and is famous for "breaking the Bank of England" in 1992, netting $1 billion in a single day. By 2025, Soros had donated over $32 billion to philanthropic causes through the Open Society Foundations, among the largest lifetime philanthropic totals of any individual.

The Mars family office manages the wealth of the Mars Inc. confectionery dynasty, with a combined family net worth estimated at $94 billion, making the Mars family one of the wealthiest in the world. Mars Inc. remains entirely private, generating over $45 billion in annual revenues from M&Ms, Snickers, Wrigley, and Pedigree pet food brands. The family office maintains a conservative, long-term investment philosophy.

The Pritzker Organization manages the wealth of the Pritzker family — founders of the Hyatt hotel chain — with a combined family net worth of approximately $28 billion split among multiple family branches. The family office has diversified aggressively beyond Hyatt, with major stakes in Royal Caribbean and global real estate. Tom Pritzker's branch focuses heavily on Asia-Pacific expansion, while Penny Pritzker (former US Commerce Secretary) runs her own investment vehicle.

Icahn Enterprises LP functions as the publicly traded family office of activist investor Carl Icahn, with approximately $15 billion in AUM spanning energy, automotive, pharmaceuticals, and real estate. Icahn is renowned for high-profile activist campaigns against companies including Apple, eBay, and Xerox, generating returns that made him one of the wealthiest investors in history. In 2023-2024, Icahn Enterprises weathered significant short-seller scrutiny from Hindenburg Research.

Rockefeller Capital Management traces back to the family office the Rockefellers established in 1882, and took its present form in 2018, when Viking Global Investors bought a majority stake in Rockefeller & Co. and Greg Fleming became chief executive. It now advises outside ultra-high-net-worth families as well as the founding one, across investment management, family office services and philanthropy.