James Harris Simons (1938–2024) was an American mathematician, billionaire hedge fund manager, and philanthropist. Known as the ‘Quant King,’ he was the founder of Renaissance Technologies and its secretive flagship Medallion Fund.
Before entering finance, Simons was a codebreaker for the National Security Agency (NSA) during the Cold War and served as chairman of the mathematics department at Stony Brook University, where he co-developed the Chern-Simons invariant in geometry and quantum field theory.