Marilyn Simons
American economist and philanthropist; co-founder and chair of the Simons Foundation; widow of the Renaissance Technologies founder Jim Simons
| Marilyn Simons
| |
|---|---|
| Born | 4 1 1951 (age 75 years old (as of 2026)
) (Forbes) |
| Occupation | Philanthropist |
| Known for | Co-founder and chair of the Simons Foundation |
| Spouse(s) | Jim Simons (died 2024) |
| Education | Stony Brook University (BA, PhD economics) |
Marilyn Simons (born 1951) is an American economist and philanthropist. She co-founded the Simons Foundation with her husband Jim Simons in 1994, and chairs it. Jim Simons, who founded the hedge fund Renaissance Technologies, died in May 2024.[1][2] Forbes attributes her family's fortune to hedge funds.[3] On 20 October 2026 the Forbes Real-Time Billionaires list ranked Marilyn Simons & family 64th in the world, with an estimated net worth of US$36.57 billion; Forbes lists the source of wealth as Hedge funds.[3][4] In the annual World's Billionaires list published in 2026, Forbes had ranked Marilyn Simons 66th, at US$32.5 billion.[5]
Education
The Simons Foundation says she earned a BA and a PhD in economics from Stony Brook University.[1] Forbes adds that she met Jim Simons at Stony Brook and records her date of birth as 4 January 1951.[3]
Renaissance Technologies and family fortune
According to the Simons Foundation, Jim Simons founded what became Renaissance Technologies in 1978. It describes the firm as a hedge fund that pioneered quantitative trading. He died in New York City on 10 May 2024, aged 86.[2] Forbes describes Marilyn Simons as his widow and gives hedge funds as the family's source of wealth.[3]
Simons Foundation
The foundation says she and Jim Simons established it in 1994 to support research in mathematics and the basic sciences. It says that together they gave billions of dollars to hundreds of causes, especially mathematics and science research and education.[2] She is the foundation's co-founder and chair.[1] IRS filings compiled by ProPublica show the Simons Foundation Inc. (EIN 13-3794889) with total assets of US$4,482,291,699 and net assets of US$3,714,733,569 for the year to December 2024. Expenses that year were US$364,993,487.[6] Forbes describes the foundation as the main funder of Math for America. It says the Simons family has given more than US$10 billion to causes including Math for America, autism research and Stony Brook University.[3]
Other roles and honours
The foundation's biography says she chairs the board of trustees of Cold Spring Harbor Laboratory, a molecular biology and genetics research centre. She is also a trustee of the National Museum of Mathematics, Rockefeller University and the Simons Laufer Mathematical Sciences Institute. She joined the board of the Stony Brook Foundation in 2024, set up the Stony Brook Women’s Leadership Council to mentor undergraduate women, and oversees the MJS Foundation, a private family foundation in New York that supports community programmes. She received the Carnegie Medal of Philanthropy with Jim Simons in 2013, was admitted to the French Legion of Honour in 2021, and was elected to the American Academy of Arts and Sciences in 2024.[1] Forbes notes that she has also been on the board of Learning Spring Elementary School, a school for children on the autism spectrum.[3]
Political activity
Federal Election Commission records show itemised contributions under her name that can be attributed to her. Recipients were mainly Democratic committees, led by the Senate Majority PAC (SMP) and House Majority PAC (HMP). They are summarised below.[7]
Across the 33 non-memo records retrieved for the 2022–2026 cycles, the filtered total is US$12,867,900 (a lower bound). The largest recipient committees, as named in the filings, were SMP (US$7,500,000), HMP (US$2,300,000), FF PAC (US$1,500,000), DCCC (US$713,700), HARRIS ACTION FUND (US$613,000).[7]
| Cycle | Total (US$, lower bound) | Records | Largest recipient committees (as filed with the FEC) |
|---|---|---|---|
| 2022 | $3,472,900 | 16 | SMP ($3,000,000); DCCC ($255,000); DNC SERVICES CORP / DEMOCRATIC NATIONAL COMMITTEE ($190,500); KIDSPAC ($10,000) |
| 2024 | $9,385,000 | 15 | SMP ($4,500,000); HMP ($2,300,000); FF PAC ($1,500,000); HARRIS ACTION FUND ($613,000) |
| 2026 | $10,000 | 2 | KIDSPAC ($10,000) |
Wealth
Forbes lists her as "Marilyn Simons & family".[3]
Wealth history
Forbes has included this entry in its annual World's Billionaires list in 2 of the editions from 2001 to 2026 checked for this profile, starting with 2025. The table gives the rank and estimated net worth in each annual list, and, where applicable, the rank and estimate in the Forbes 400 list of the richest Americans.[5][3]
| Year | World's Billionaires rank | Net worth (US$ bn) | Forbes 400 rank | Forbes 400 net worth (US$ bn) |
|---|---|---|---|---|
| 2024 | – | – | 31 | 31.0 |
| 2025 | 57 | 31.0 | 29 | 32.5 |
| 2026 | 66 | 32.5 | 27 | 36.6 |
International and political links
This section uses the same ten headings for every profile in this series. Only specific, sourced actions are included; company-level and foundation-level actions are labelled as such. Where nothing was found, the entry reads "No documented involvement found in sources checked."
Israel (investments, operations, donations, contracts, statements)
No documented involvement found in sources checked.
Zionist or pro-Israel organisations and lobbying groups
No documented involvement found in sources checked.
Jewish communal charities
No documented involvement found in sources checked.
Gulf states
No documented involvement found in sources checked.
China
No documented involvement found in sources checked.
Russia
No documented involvement found in sources checked.
India
No documented involvement found in sources checked.
Palestinian or Arab causes
No documented involvement found in sources checked.
Home government
For her US federal political donations see Political activity.[7]
Other international links
She was admitted to the French Legion of Honour in 2021.[1]
See also
External links
Notes
- ↑ 1.0 1.1 1.2 1.3 1.4 Simons Foundation, Marilyn Simons, Ph.D. – Chair Simons Foundation, accessed 20 October 2026, accessed 20 October 2026.
- ↑ 2.0 2.1 2.2 Thomas Sumner, Simons Foundation Co-Founder, Mathematician and Investor Jim Simons Dies at 86 Simons Foundation, 10 May 2024, accessed 20 October 2026.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Forbes, Forbes profile record for Marilyn Simons & family (Forbes data feed behind forbes.com/profile/marilyn-simons/) Forbes, live record, read 20 October 2026, accessed 20 October 2026.
- ↑ Forbes, Forbes Real-Time Billionaires data feed Forbes, live; downloaded 20 October 2026 11:51 UTC, accessed 20 October 2026.
- ↑ 5.0 5.1 Forbes, Forbes World's Billionaires list data feed, annual editions 2001–2026 (one file per year at this path with the year substituted; all 26 files downloaded and read) Forbes, annual lists; downloaded 20 October 2026, accessed 20 October 2026.
- ↑ ProPublica Nonprofit Explorer, Simons Foundation Inc (EIN 13-3794889) – Nonprofit Explorer record with IRS filing data ProPublica Nonprofit Explorer, IRS filings as processed by ProPublica, accessed 20 October 2026.
- ↑ 7.0 7.1 7.2 U.S. Federal Election Commission, OpenFEC Schedule A (itemised individual contributions) query, contributor name "SIMONS, MARILYN"; 2026 cycle shown in link, the 2022, 2024 and 2026 cycles were queried together with the same parameters; top 100 records by amount; compiler filtered records by employer/occupation and name and excluded memo entries U.S. Federal Election Commission, data as filed; queried 20 October 2026, accessed 20 October 2026.