Jim Simons, who was a noted differential geometer (for instance being one of the discoverers of Chern-Simons theory), then a successful hedge fund manager, and finally a major philanthropist to mathematics and the sciences, died today, aged 86: https://www.nytimes.com/2024/05/10/business/dealbook/jim-simons-dead.html .
One can debate whether the economic model of first encouraging the concentration of wealth by billionaires, and then relying on such billionaires for philanthropy, is the most effective or just mechanism for creating public goods, but certainly Jim made some very important investments in the modern infrastructure of mathematics and science, with his foundation being a significant funder of the arXiv for instance, and of major institutes such as the SLMath institute (formerly MSRI), as well as the 2026 ICM that is to be held in Philadelpha. I was also fortunate to be supported by a Simons Investigator Award for over a decade, which in turn supported a large number of research activities of my group here at UCLA.
I only interacted with Simons a few times (we were both on the SLMath Board of Trustees, but our interactions were almost entirely via Zoom), but he came across as sincere in his support of the sciences, and I hope the Simons Foundation will continue that support in the future.