Heising-Simons Foundation

Heising-Simons Foundation

The Heising-Simons Foundation was established in 2007 by Elizabeth Simons and Mark Heising. Simons is the daughter of Renaissance Technologies founder James Simons. The foundation maintains its headquarters in Los Altos, California. Grantmaking covers climate and clean energy, science research, early childhood education, and human rights. The foundation makes direct grants and supports organizations including the Environmental Defense Fund and Human Rights Watch. It also backs journalism and technology-society initiatives. Geographic reach centers on the United States with additional international human rights work. Positions include limited partner commitments through Medley Partners to Resolute Ventures, EQT, TA Associates, Charterhouse Capital Partners, and Endless LLP. The foundation lists 810 million dollars in total assets per recent filings. Mark Heising founded Medley Partners Management LLC, which manages private market investments for the family network. Additional offices are not disclosed. The family maintains the Heising-Simons Action Fund as a separate advocacy vehicle. December 2024: Sponsored International Human Rights Day events in San Francisco. The foundation operates with a dedicated board that includes next-generation family members. Caitlin Heising serves as vice chair. This governance model keeps investment advice at Medley Partners while grant decisions remain inside the foundation structure.