Who is Marilyn Simons?
Marilyn Simons is the co-founder and chair of the Simons Foundation, one of the largest private funders of basic science research in the United States, and the widow of the quantitative investor Jim Simons. The 2026 Forbes 400 values her and her family at $36.6 billion and ranks her fifth among America’s richest women, according to Hola! USA on 18 September 2026 1.
How did Marilyn Simons make her money?
Her wealth is tied to Renaissance Technologies, the quantitative hedge fund that Jim Simons founded in 1978 as Monometrics and renamed in 1982. Hola! USA describes the family’s wealth as coming from hedge funds. Forbes’ March 2026 list of the richest women valued her at $32.5 billion as of 1 March 2026 and identified her as Jim Simons’s widow 127.
Education
She holds a B.A. and a Ph.D. in economics from Stony Brook University. The sources reviewed do not report her birth date or birthplace 34.
The Simons Foundation
She co-founded the foundation in 1994 with her husband, served as its president until July 2021 and is now chair of its board of trustees. She also chairs the board of Cold Spring Harbor Laboratory, sits on the boards of the Turkana Basin Institute, LearningSpring School and East Harlem Scholars Academies, and founded the Stony Brook Women’s Leadership Council 34. Read Marilyn Simons’s companies and roles.
Honors
She shared the Carnegie Medal of Philanthropy with Jim Simons in 2013, was inducted into the French Legion of Honor in 2021 and was elected to the American Academy of Arts and Sciences in 2024 345.
Family
She married Jim Simons in 1977. He died on 10 May 2024 in New York at the age of 86. KSAT reports that he was survived by his wife, three children, five grandchildren and one great-grandchild 67. Read Marilyn Simons’s family.
Marilyn Simons net worth
The 2026 Forbes 400 put her family at $36.6 billion in September 2026, about ₹3.4 lakh crore at ₹94 to the dollar, up from $32.5 billion on 1 March 2026 12. See Marilyn Simons net worth and our ranking of the wealthiest women in the world.