Our People Mark Heising Vice Chair of the Board Mark Heising is an investor and philanthropist. He founded Medley Partners, a private market investment firm, in 2004. His philanthropic work focuses on climate, clean energy, science, and public-interest institutions. Mark serves as Chair of the Environmental Defense Fund and on the advisory council for the Stanford Doerr School of Sustainability. He is a Trustee of the Institute for Advanced Study and serves on the boards of the Heising-Simons Foundation, the Heising-Simons Action Fund, and the Clean Power Institute. In 2016, Mark and his wife, Liz Simons, joined the Giving Pledge, publicly committing the majority of their wealth to philanthropic causes. Mark earned a bachelor’s degree in Physics and a master’s degree in Electrical Engineering and Computer Sciences from the University of California, Berkeley.