From curing malaria to rewriting America's education system, the largest private foundations in the U.S. wield influence that rivals governments. They can launch global health campaigns, fund scientific breakthroughs, rebuild cities, or preserve art for future generations. At their best, they tackle the world's biggest problems with long-term focus and deep pockets. At their most opaque, they're tax-efficient vehicles for the ultra-wealthy to steer culture, politics, and society—quietly, and sometimes forever.
So, where is all this power concentrated? In a few dozen names you know—and a few you probably don't. Gates. Bloomberg. Walton. Getty. Cargill. Some of the largest philanthropic foundations in America today were seeded with old money from Standard Oil and Ford Motors. Others were born from software, semiconductors, cereal, or hedge fund billions. Together, these 100 foundations control hundreds of billions of dollars—and through strategic giving, they're reshaping everything from climate change to kindergarten classrooms. Below, we dive into the top 20 in depth—what they fund, how they got started, and what makes them so powerful. Then we list the full top 100, ranked by assets.
PS. To compile this full list below, I reached out to a friend who works for a large foundation in New York City. I thought this was going to be a huge task, but it turns out all private charities in the US are required to report their assets to the IRS every year. So once we knew where to look, the rest was fairly easy to organize 🙂 But then we also took the time to understand who and how the top 20 earned their fortunes… as you'll see in a moment when you get to the list.
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Top 100 U.S. Private Foundations by Asset Size (2025)
One interesting thing to note is the difference between a "spend down" foundation and one that is designed to live in "perpetuity". Modern philanthropists seem to prefer setting up spend-down foundations, which aim to give away all assets in a relatively short period. For example, the Bill & Melinda Gates Foundation plans to give away all of its assets within 20 years of Bill and Melinda's deaths. Old school tycoons like Ford, Kellogg, and Rockefeller preferred setting up foundations that live on for as long as possible by giving away only the profits produced by interest. That's how charities like the Rockefeller Foundation and the Carnegie Corporation have managed to stick around for over 100 years. It's not my place to say which system is better for the world, but I do hope I'm in the position to make that decision myself someday!
#1. Bill & Melinda Gates Foundation – $75.2 billion
Source: Microsoft and diversified investments. The Gates Foundation has four areas of focus: 1) Global Development Division – "works to help the world's poorest people lift themselves out of hunger and poverty" 2) Global Health Division – "aims to harness advances in science and technology to save lives in developing countries" 3) United States Division – "works to improve U.S. high school and postsecondary education and support vulnerable children and families in Washington State" 4) Global Policy & Advocacy Division – "seeks to build strategic relationships and promote policies that will help advance our work."
#2. Lilly Endowment Inc. – $62 billion
Source: Established in 1937 by Josiah K. Lilly, Sr, son of the founder of pharmaceutical giant Eli Lilly and Company. Its wealth is rooted in Eli Lilly stock, which has surged in value, notably due to breakthrough drugs in recent years. Focus: Primarily supports community development, education, and religious causes, with a special emphasis on its home state of Indiana. The endowment has historically devoted the majority of its grants to Indiana institutions, echoing J.K. Lilly's desire to "nurture the human spirit, intellect, and character" close to home. Notable: Thanks to booming pharma stock, Lilly Endowment's assets roughly tripled in a short span – from $7 billion in 2014, to $21 billion in 2019, to over $60 billion by the end of 2023.
#3. Howard Hughes Medical Institute – $25.6 billion
Source: Created in 1953 by aviation and film tycoon Howard Hughes, who endowed it with profits from Hughes Aircraft. Today, the institute's wealth comes from a diversified endowment built on Hughes's original bequest and subsequent investments. Focus: HHMI is an operating foundation dedicated to biomedical research and science education. Rather than mainly giving grants, it directly employs hundreds of elite scientists (HHMI Investigators) and supports research centers, advancing fundamental biology and medicine "for the benefit of humanity." Over the past five years, it has spent about $4.6 billion on scientific research and education programs. It is the largest private medical foundation in the United States.
#4. Open Society Foundations – $25 billion
Source: Founded by financier George Soros, who has transferred the bulk of his hedge fund fortune (estimated at $32 billion in total gifts) into OSF. OSF supports efforts "across the globe fighting for freedom of expression, transparency, accountable government, and societies that promote justice and equality."
#5. Ford Foundation – $16 billion
Source: Established in 1936 by Ford Motors founder Henry Ford and his son Edsel with the simple mission to "Advance Human Welfare". In 1969, the foundation gave $1 million to the Children's Television Workshop to fund a new program called Sesame Street.
#6. The Robert Wood Johnson Foundation – $13.7 billion
Source: Established in 1972 by Robert Wood Johnson II, whose father co-founded Johnson & Johnson. The foundation is the largest philanthropy in the US that is focused solely on health care. Every year, the foundation makes $400 million worth of grants to various health-related causes, especially in the areas of childhood obesity, poverty, and the training of doctors and nurses.
#7. The William and Flora Hewlett Foundation – $14 billion
Source: William Hewlett was the co-founder of Hewlett-Packard. An initial HP stock donation of $18 million grew exponentially; today, the endowment stands around $14 billion. Their foundation "supports educational and cultural institutions and to advance certain social and environmental issues." Every year, the foundation aims to give away $300-400 million in grants. Most grants are well under $1 million, but the foundation has given several very large gifts to Stanford University, UC Berkeley, and the Climate Works Foundation.
#8. J. Paul Getty Trust – $12.5 billion
Source: Upon Jean Paul Getty's death, over $660 million of his estate went to the Getty Trust. Today, it's worth over $12 billion. Getty struck oil in Saudi Arabia in the 1930s and 1940s, amassing a vast personal fortune which he left largely to this trust upon his death in 1976. The Getty Trust is an operating foundation that funds the J. Paul Getty Museum in Los Angeles (one of the world's wealthiest art institutions), the Getty Research Institute, and the Getty Conservation Institute. Getty was famously frugal – he once negotiated the ransom for his kidnapped grandson only after the kidnappers mailed the boy's ear, cementing Getty's public image as the penny-pinching billionaire.
#9. Bloomberg Philanthropies – $12 billion
Michael Bloomberg has pledged the majority of profits from his financial data company, Bloomberg L.P., to philanthropy. Bloomberg Philanthropies takes an entrepreneurial, data-driven approach. It often works through large-scale partnerships – for instance, a $500 million Beyond Carbon initiative to fight climate change, and major gifts to Johns Hopkins University (Bloomberg's alma mater). Michael Bloomberg has already given over $21 billion to philanthropy in his lifetime.
#10. Silicon Valley Community Foundation – $10 billion
Source: Contributions from many wealthy tech entrepreneurs and corporations. SVCF was formed in 2007 by merging two Bay Area community foundations, and it quickly became a favorite conduit for Silicon Valley billionaires' charitable funds (Facebook's Mark Zuckerberg notably gave nearly $1 billion in Facebook shares to SVCF in 2013.
#11. Gordon and Betty Moore Foundation – $9.5 billion
Source: Gordon Moore is the co-founder of Intel. The foundation "seeks to develop outcome-based projects that will improve the quality of life for future generations." In recent years, the foundation has been focused on improving patient care programs and environmental conservation. In 2007, the foundation gave $100 million to establish a nursing school at the University of California, Davis.
#12. W. K. Kellogg Foundation – $9.4 billion
Source: Will Keith Kellogg was the founder of Kellogg's, makers of all your favorite breakfast cereals. WK Kellogg established his foundation in 1934 with $66 million worth of company stock. That was equal to roughly $1 billion at the time. Thanks to Kellogg Co.'s growth (and some recent corporate spinoffs), the foundation's assets have swelled. Today, the foundation controls over $9 billion in assets. True to Mr. Kellogg's instruction to work for the "health, happiness, and well-being of children, without discrimination," the foundation supports early childhood education, health equity, and economic opportunity, with significant work in priority places like Michigan, Mississippi, New Mexico, and Native American communities.
#13. Margaret A. Cargill Philanthropies – $9.2 billion
Source: The quietly amassed fortune of Margaret Cargill (1920–2006), an heir to the Cargill agribusiness empire. Her wealth (largely shares of Cargill Incorporated, later converted to investments) was left to her philanthropies after her passing.
#14. The John D. and Catherine T. MacArthur Foundation – $6 billion
Source: John D. MacArthur made his first fortune in the insurance business through his company, Bankers Life and Casualty Company. He then increased his fortunes greatly by investing in Palm Beach, Florida real estate. When John died in 1978, he left an estate worth around $1 billion (including vast Florida real estate holdings) to found this philanthropy. MacArthur funds programs in fields such as international peace and security (e.g., nuclear nonproliferation), climate change, public interest journalism, criminal justice reform, and technology in the public interest. It takes on complex, systemic challenges. The foundation is also famous for its no-strings-attached "Genius Grants" – the MacArthur Fellows program – which awards $800,000 over five years to about two dozen exceptionally creative individuals annually.
#15. The David and Lucile Packard Foundation – $8.3 billion
Source: David Packard was the other co-founder of Hewlett-Packard (see #7 above). Their foundation's goal is to "improve the lives of children, enable creative pursuit of science, advance reproductive health, and conserve and restore earth's natural systems."
#16. The Andrew W. Mellon Foundation – $8.0 billion
Founded from the Mellon family's banking and industrial fortune, this foundation is the largest arts and humanities funder in the U.S. It supports museums, libraries, and universities, with a recent focus on racial justice through cultural heritage and historical storytelling.
#17. The Rockefeller Foundation – $6.3 billion
Established by Standard Oil founder John D. Rockefeller in 1913, this century-old institution pioneered modern philanthropy. Today, it funds global health, economic resilience, and climate initiatives, staying true to its mission of promoting the well-being of humanity worldwide.
#18. Tulsa Community Foundation – $5.8 billion
Launched by billionaire George Kaiser, TCF pools donor-advised funds to support Tulsa-focused causes like early education, healthcare, and community revitalization. Despite its local focus, its asset base rivals many national foundations.
#19. Walton Family Foundation – $5.7 billion
Built from Walmart wealth, the Walton Foundation emphasizes K–12 education reform, environmental conservation, and regional development. It's a major backer of charter schools and sustainability efforts in the American South and Midwest.
#20. Greater Kansas City Community Foundation – $5.5 billion
Founded in 1978, GKCCF channels billions in charitable funds from local and national donors. Its programs support education, healthcare, and the arts, making it one of the largest and most active community foundations in the country.
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