James Simons is chairman of the Simons Foundation and board chair and founder of Renaissance Technologies. Prior to his financial career, Simons was chairman of the mathematics department at Stony Brook University, taught mathematics at the Massachusetts Institute of Technology (MIT) and Harvard University, and was a cryptanalyst at the Institute for Defense Analyses. Simons holds a B.S. from MIT and a Ph.D. from the University of California, Berkeley. In 1976, he won the Veblen Prize of the American Mathematics Society for his work in geometry. He is a trustee of the Stony Brook Foundation, Rockefeller University, MIT, Brookhaven National Laboratory, the Mathematical Sciences Research Institute, New York Genome Center and the Institute for Advanced Study, and is a member of the National Academy of Sciences, the American Academy of Arts and Sciences and the American Philosophical Society.

You can watch his public lecture given on the opening day of the ICM 2014 here.