Mark Heising is vice chair of the board of the Heising-Simons Foundation. Mark established Medley Partners in 2004, a firm specializing in private market investments. Before that, he founded VLSI Cores, a company focused on the design and licensing of cryptographic integrated circuits. He is named in six U.S. Patents in cryptography, data compression and data communications.

He holds the position of Chair for the Environmental Defense Fund, serves on the advisory council of the Stanford Doerr School of Sustainability, and is a trustee for the Institute for Advanced Study. He is also a member of the Board for the Heising-Simons Action Fund, a fund he and his wife, Liz Simons, established in 2007.

Mark and his wife, Liz Simons, took the Giving Pledge in 2016, publicly committing the majority of their wealth to philanthropic causes. Mark earned a BS in Physics and a MS in Electrical Engineering and Computer Sciences from the University of California at Berkeley. Mark Heising and Liz Simons founded the Foundation in 2007. You can read the letter they wrote about why they joined the Giving Pledge here.