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Person

Susan Mandel

Nationality:

American
Spouse:

Stephen Mandel
Main Philanthropy:

Zoom Foundation

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Susan Mandel is a philanthropist and the wife of hedge fund billionaire Stephen Mandel. They are both co-trustees of the Zoom Foundation and are major funders of Democratic campaigns. 1 The Zoom Foundation is a left-of-center grantmaking organization that primarily makes grants through the use of donor-advised funds (DAF) which serves to conceal the recipient of its grantees. 2

Family

Susan Mandel is married to American billionaire and philanthropist Stephen Mandel, who is best known for having founded Lone Star Capital. As of December 2024, Stephen Mandel had a net worth of $2.5 billion. Prior to starting his own hedge fund, Mandel worked for Tiger Capital, a hedge fund founded by Juilian Robertson. 1

Stephen and Susan Mandel founded the nonprofit organizations Zoom Foundation and Lone Pine Foundation and sit on the national board of directors for teacher placement and training organization Teach for America. 1 Stephen is reported to be one of the top donors to Democratic campaigns and in 2020 donated $2 million to the Lincoln Project, a campaign opposing Donald Trump’s presidential campaign. 3

In 2022, Susan and Stephen Mandel reportedly gave $17.7 million to political campaigns, the majority of which was to Democratic campaigns, making them the 17th largest donors during the election cycle. 4

Philanthropy

Zoom Foundation

Susan Mandel, alongside her husband Stephen Mandel, co-founded the Zoom Foundation in 2001 where they continued to serve as co-trustees as of 2025. The Zoom Foundation’s 2024 tax returns showed that it has $1.4 billion in assets and made $63.1 million in grants paid, all of which were made to Fidelity Investments Charitable Gift Fund, a donor-advised fund provider. 5

According to Inside Philanthropy , the Zoom Foundation used 99.9 percent of its grantmaking to make contributions to DAFs, which make grants on behalf of their donors while not being required to directly disclose the grantor-grantee relationships. Despite the anonymity of its grantmaking, the Zoom Foundation is known to have made grants to the Environmental Defense Fund, Teach for America, Blue Meridian, and community organizations in Greenwich, Connecticut and in New York, according to Inside Philanthropy. 2

Environmental Defense Fund

As of 2025, Susan Mandel was a board member of the Environmental Defense Action Fund as well as a trustee of its sister organization Environmental Defense Fund. 6

Connecticut Project

As of 2025, Susan Mandel was a member of the board of directors for the Connecticut Project and the Connecticut Project Action Fund. 7 The Connecticut Project is a nonprofit organization that advocates government funding of welfare programs to address social issues in Connecticut, including advocating subsidized housing, child care, and education programs. It also advocates for early voting policies. 8

The Argument

As of August 2025, Susan Mandel was listed as one of the investors into The Argument, a left-of-center publication started by former Atlantic writer Jerusalem Demsas with staff from media sites Vox and Semafor to write on “what liberalism is for, rather than just what it’s against.” 9 The new publication raised $4 million “at a $20 million valuation,” while in a statement Demsas argued “To move out of this post-liberal, populist moment towards a better future…will require our government, culture, politics, and people to recommit ourselves to liberal values.” 9 Others listed as investors include Arnold Ventures, Open Philanthropy, Gaurav Kapadia, Rachel Pritzker, Simone Coxe, John Wolthuis, Patrick Collison and Emergent Ventures. 9

Political Activities

During the 2024 election cycle, Susan Mandel made $7.3 million in contributions to political campaigns, the majority of which were matched by her husband Stephen Mandel, as well as to Democratic Party-aligned campaigns. The largest contributions included $2.5 million to Future Forward USA Action, $2.5 million to Environmental Defense Fund Action Votes, and $1 million to Republican Accountability PAC. 10

In 2024, Susan and Stephen Mandel made a $250,000 contribution to One Giant Leap PAC, a political action committee supporting Rep. Mikie Sherrill’s (D-NJ) bid for New Jersey governor. 11

Between the 2008 and 2012 presidential election, Mandel supported Barack Obama’s campaigns as a bundler, coordinating $198,650 in contributions. 12

Years of Living Dangerously

Susan Mandel produced “Years of Living Dangerously,” a television series released in 2014 that covered weather events and associated them with the environmentalist concept that humans are exacerbating climate change. 13 14

References

  1. “Stephen Mandel Jr.: Age, Net Worth, Biography & More.” Mabumbe. December 19, 2024. https://mabumbe.com/people/stephen-mandel-jr-age-net-worth-biography-more/. 
  2. Kavate, Michael. “The Top 10 Hedge Fund Philanthropists.” March 14, 2023. https://www.insidephilanthropy.com/home/2023-3-14-the-top-10-hedge-fund-philanthropists-in-the-us.
  3. Kampeas, Ron. “Meet the leading Jewish political donors in this US election cycle.” Times of Israel. September 25, 2020. https://www.timesofisrael.com/meet-the-leading-jewish-political-donors-in-this-us-election-cycle/.
  4. Mccrank, John. “How Wall St and billionaires have donated to U.S. elections.” Reuters. November 8, 2022. https://www.reuters.com/world/us/how-wall-st-billionaires-have-donated-us-elections-2022-11-08/.
  5. Return of Organization Exempt from Income Tax (Form 990PF). Zoom Foundation. 2024.
  6. “Susan Mandel.” LittleSis Public Accountability Initiative. Accessed July 6, 2025. https://littlesis.org/person/49918-Susan_Mandel.
  7. “Our Boards of Directors.” The Connecticut Project. Accessed July 6, 2025. https://ctproject.org/our-boards.
  8. “2024 Inaugural Report.” The Connecticut Project. Accessed July 6, 2025. https://24471326.fs1.hubspotusercontent-na1.net/hubfs/24471326/2024%20The%20Connecticut%20Project%20and%20The%20Connecticut%20Project%20Action%20Fund%20Inaugural%20Report.pdf?hsCtaAttrib=165803790604.
  9. Tani, Max. “The left gets a new publication.” Semafor, August 17, 2025. https://www.semafor.com/article/08/17/2025/with-the-argument-the-left-gets-a-new-publication?utm_medium=media&utm_campaign=flagshipnumbered1&utm_source=newslettercta
  10. “Mandel, Stephen Frank Jr. & Susan Z.: Donor Detail.” OpenSecrets. Accessed July 6, 2025. https://www.opensecrets.org/outside-spending/donor_detail/2024?id=U0000000053&name=Mandel%2C+Stephen+Frank+Jr.+%26+Susan+Z.&super_only=N&type=I.
  11. Wildstein, David. “Super PAC backing Sherrill has raised $1.7 million.” New Jersey Globe. October 15, 2024. https://newjerseyglobe.com/campaigns/super-pac-backing-sherrill-has-raised-1-7-million/. 
  12. “Bundlers Barack Obama (D).” OpenSecrets. Accessed July 6, 2025. https://www.opensecrets.org/pres08//bundlers?id=N00009638. 
  13. “Sue Mandel.” IMDb. Accessed July 6, 2025. https://www.imdb.com/name/nm6729626/.
  14. “Years of Living Dangerously.” IMDb. Accessed July 6, 2025. https://www.imdb.com/title/tt2963070/.
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