Marilyn Simons & family

Marilyn Simons & family is among the world's most closely watched billionaires from UNITED STATES, with an estimated fortune of $32.5B. The bulk of Marilyn Simons & family's wealth comes from Hedge funds, closely tied to Hedge funds. Marilyn Simons is an American philanthropist and advocate, recognized for her significant contributions to scientific research and education. With an estimated net worth of $32.5 billion, she is a leading figure in the world of philanthropy. Her wealth stems from her late husband, Jim Simons, a hedge fund legend and the founder of Renaissance Technologies, a quantitative trading firm. She co-founded the Simons Foundation in 1994, which has become a major supporter of basic science, mathematics, and autism research. Throughout her career, Simons has championed STEM research, education, and outreach, actively serving on various boards and councils. Her dedication to philanthropy and her influence in the scientific community have made her a notable figure in both finance and the advancement of knowledge. Key career milestones include Co-founded the Simons Foundation (1994); Joined the Cold Spring Harbor Laboratory Board of Trustees (2008); Founded the Stony Brook Women's Leadership Council (2014); Chair of the Board of Trustees of the Cold Spring Harbor Laboratory (2019). This profile documents verified holdings, career milestones, and multi-year net worth history drawn from Forbes rankings, company filings where available, and our editorial methodology. Readers use it to understand how public markets, private company stakes, and major business bets shape one of the largest personal fortunes on record. Wealth estimates move with stock prices, funding rounds, and disclosed transactions—figures on this page are research estimates, not cash balances. We publish year-by-year net worth history when verified data exists, link to primary sources, and update profiles when Forbes Real-Time Billionaires or major filings change the picture materially. For investors and researchers, the most useful reading pairs the headline number with ownership structure, geography, sector exposure, and the multi-year history chart on this page—especially during volatile markets when single-day moves can shift rankings without any operational change at the underlying companies.