The Peterffy Foundation is a left-of-center private philanthropic foundation established by billionaire entrepreneur Thomas Peterffy, the founder of Interactive Brokers. The Foundation is now run by Peterffy’s family on a volunteer basis, including Alexandra Peterffy, Catherine Peterffy, and William (Will) Peterffy. ¹ While Thomas Peterffy is a major donor to the Republican Party, ² the Peterffy Foundation provides grants primarily to organizations working on left-of-center environmentalist issues, climate policy, and indigenous causes throughout North, Central, and South America. ^{3  4}

The Peterffy Foundation uses three funding portfolios for its philanthropy. ⁵ William Peterffy uses Environmental, Social, and Corporate Governance (ESG) investing to influence direct capital toward companies and projects that prioritize environmental sustainability and social impact, supporting his belief that markets can be reoriented to support “ecological and social well-being,” rather than profit. ⁶

Funds

One Small Planet Philanthropic Fund was founded in 2015 as part of the Peterffy Foundation. Using three funding portfolios, the Peterffy Foundation includes the Living Forest Project, Reweaving the Web, and One Small Planet funds. ⁷

One Small Planet

The Peterffy Foundation funds and supports One Small Planet, an initiative focused on environmental issues, including land, ecological restoration, and economic models that support the environment. One Small Planet is run by Will Peterffy with the goal of reshaping the global economy so that financial systems support the environment. The organization states that wealth is not related to money, but that it views wealth as a “holistic metric of well-being” and strives for a world that is “decolonized.” ⁸

One Small Planet invests heavily in startups and eco-based businesses. Symbrosia, a Hawaii-based company developing SeaGraze, an additive for beef and dairy producers, raised $5.8 million with lead investors Idemitsu and One Small Planet. Idemitsu is a Japanese petroleum company that operates oil platforms, refineries, and produces petroleum, oils, and petrochemical products. ^{9  10}

Living Forest Fund

The Peterffy Foundation funds and supports The Living Forest Fund, an environmental initiative focused on indigenous communities, particularly prioritizing women. ⁵

Reweaving the Web

The Peterffy Foundation funds and supports Reweaving the Web, an environmental initiative focused on the relationship between the environment and people. ⁵

Grantmaking

The Peterffy Foundation has funded Mothers of the Amazon, a left-leaning California-based environmentalist organization that focuses on indigenous communities and the Amazon Rainforest, since its inception in 2020. ⁵ In 2024, the Peterffy Foundation allocated $300,000 to Mothers of the Amazon. ¹¹

The Women’s Earth and Climate Action Network (WECAN), a left-leaning environmental and social advocacy group that advocates for climate policy change, weather-dependent energy, and women, particularly Indigenous and racial minority women, to be placed in energy policy leadership roles, has received multi-year funding from the Peterffy Foundation, specifically through the Living Forest Project, including $100,000 in 2024. ^{11  12}

In 2024, the Peterffy Foundation allocated $1.6 million to Quipa Inc., a left-of-center New York-based environmentalist group that builds alliances between organizations and Indigenous communities in the “Global South” to promote climate policy, environmental activism, and education. ¹¹

In 2024, the Peterffy Foundation awarded grants to several left-of-center advocacy organizations, including the Planned Parenthood Federation of America, the Southern Environmental Law Center (SELC), the Tides Foundation, and One Earth. ¹¹

In 2023, the Peterffy Foundation provided support to Oregon Wild, an environmentalist organization that focuses on wildlands, wildlife, and waters. ¹²

In 2021, the Peterffy Foundation awarded a grant of $87,000 to the Giniw Collective, a left-of-center activist group that advocates for “land defense, decolonization, and to carry our words into action,” through its fiscal sponsor Unkitawa. ¹³

Leadership

Founder

Thomas Peterffy, the billionaire founder of Interactive Brokers and the Peterffy Foundation, has been an outspoken critic of socialism in the United States, due to his early life under a socialist regime in Hungary. During the 2012 U.S. presidential election, he personally financed and appeared in national television advertisements warning that the U.S. could be on a “slippery slope” toward socialism and urged viewers to vote Republican. ¹⁴ Peterffy has donated to Republican Party candidates and right-leaning causes, including $250,000 to Donald Trump’s 2020 presidential campaign. ¹⁵ In 2024, Peterffy donated approximately $7 million to Republicans and party organizations, and $844,660 to the Trump 47 Committee joint fundraising campaign. ^{16  17  2}

Peterffy does not sit on the board or actively manage the foundation, which is “under the stewardship of his children” according to the One Small Planet website. ¹⁸

Investment Committee Chair

Will Peterffy is the chair of the investment committee for the Peterffy Foundation and the CEO and founder of One Small Planet. He took a formal leadership role in the environmental, social, and corporate governance (ESG) efforts at Interactive Brokers after joining the company in 2019 to lead its ESG initiative as the chairman of the ESG committee. Will Peterffy is on the board of the Collective Heritage Institute (commonly known as Bioneers), an environmental and social advocacy nonprofit. ^{19  20}

1. The Peterffy Foundation, Return of Private Foundation (Form 990-PF), 2024, Part VII, Section 1, (a). Accessed March 12, 2026. https://projects.propublica.org/nonprofits/organizations/472351448/202521359349101397/full
2. [1] Thomas Peterffy – Individual Contributions, Years 2023-2024, “Thomas Peterffy.” Federal Election Commission. Accessed March 16, 2026. https://www.fec.gov/data/receipts/individual-contributions/?contributor_name=Thomas+Peterffy&two_year_transaction_period=2024&min_date=01%2F01%2F2023&max_date=12%2F31%2F2024
3. Peterffy Foundation. Hinchilla. Accessed March 12, 2026. https://www.hinchilla.com/funders-us/472351448-peterffy-foundation
4. The Peterffy Foundation. Cause IQ. Accessed March 12, 2026. https://www.causeiq.com/organizations/the-peterffy-foundation,472351448/
5. Philanthropic Fund – 2023 Annual Report. 2024. Accessed March 13, 2026. https://one-small-planet.paperturn-view.com/pdf?pid=ODg8838624&v=4
6. Massa, Annie. “A Billionaire’s Heir Hangs Up His Healing Crystal to Fix Capitalism.” Bloomberg Business. March 2, 2022. Accessed March 13, 2026. https://www.bloomberg.com/news/features/2022-03-02/billionaire-wall-street-heir-william-peterffy-takes-esg-role-to-fix-capitalism
7. Philanthropy – Preserving and Regenerating Life. One Small Planet. Accessed March 13, 2026. https://www.onesmallplanet.org/one-small-planet-water
8. About. One Small Planet. Accessed March 13, 2026. https://www.onesmallplanet.org/one-small-planet-about
9. Organization – One Small Planet. Crunchbase. Accessed March 13, 2026. https://www.crunchbase.com/organization/one-small-planet
10. “Symbrosia Raises Additional $5.8M in Series A-1 Funding to Accelerate Commercial Scale-Up of SeaGraze.” Symbrosia. December 16, 2025. Accessed March 13, 2026. https://symbrosia.co/blog/symbrosia-raises-additional-58m-in-series-a-1-funding-to-accelerate-commercial-scale-up-of-seagraze
11. The Peterffy Foundation, Return of Private Foundation (Form 990-PF), 2024, Part XIV, Section 3, a. Accessed March 12, 2026. https://projects.propublica.org/nonprofits/organizations/472351448/202521359349101397/full
12. Peterffy Foundation – 2023 Annual Report. 2024. Accessed March 13, 2026. https://cdn.prod.website-files.com/633732ce03e958ae541b44b1/66855ef8c5a4e1630c19533f_Peterffy%20Foundation%202023%20Report.pdf
13. The Peterffy Foundation, Return of Private Foundation (Form 990-PF), 2021, Part XIV, Section 3, a. Accessed March 12, 2026. https://projects.propublica.org/nonprofits/organizations/472351448/202221519349100517/full
14. Durgy, Edwin. “Billionaire Thomas Peterffy Publishes Anti-Socialism Political Advertisement.” Forbes. October 15, 2012. Accessed March 16, 2026. https://www.forbes.com/sites/edwindurgy/2012/10/15/billionaire-thomas-peterffy-publishes-anti-socialism-political-advertisement/
15. Tindera, Michela. “Here Are the Billionaires Who Donated to Donald Trump’s 2020 Presdiential Campaign.” Forbes. February 19, 2021. Accessed March 16, 2026. https://www.forbes.com/sites/michelatindera/2021/02/19/here-are-the-billionaires-who-donated-to-donald-trumps-2020-presidential-campaign/
16. Glasser, Susan. “How Republican Billionaires Learned to Love Trump Again.” The New Yorker. October 18, 2024. Accessed March 16, 2026. https://www.newyorker.com/magazine/2024/10/28/how-republican-billionaires-learned-to-love-trump-again
17. Thomas Peterffy – Individual Contributions, Years 2023-2024, “Trump 47 Committee.” Federal Election Commission. Accessed March 16, 2026. https://www.fec.gov/data/receipts/individual-contributions/?committee_id=C00867937&contributor_name=Thomas+Peterffy&two_year_transaction_period=2024&min_date=01%2F01%2F2023&max_date=12%2F31%2F2024
18. “One Small Planet Water.” One Small Planet Water. Accessed March 31, 2026. https://www.onesmallplanet.org/one-small-planet-water.
19. Interactive Brokers Group, INC. United States Securities and Exchange Commission, Schedule 14A. 2023. Accessed March 16, 2026. https://www.sec.gov/Archives/edgar/data/1381197/000114036123010698/ny20005483x2_def14a.htm
20. Interactive Brokers Group, INC. 2024 Annual Meeting of Stockholders – Proxy Vote. 2024. Accessed March 16, 2026. https://materials.proxyvote.com/default.aspx?docHostID=KMGp/qJ/UA91ZN4cJ8O/dfoZqtgS8JPhoULTv+DzJ/o=&encr=Y