Founded in 2004 by Mark Heising, Medley Partners is the private markets investment manager for the foundations affiliated with Jim Simons’ family.

Medley invests primarily in limited partnerships across the private asset classes, including buyout, growth equity, venture capital, real estate and credit in the United States, Europe and Asia. We also participate in co-investment opportunities with our existing managers.

Our targeted asset classes:

Corporate Equity

  • Buyout
  • Growth equity
  • Venture capital


  • Corporate credit and real estate credit
  • Direct lending
  • Distressed and special situations
  • Structured credit

Real Estate

  • Value-add and opportunistic
  • Funds and direct

We manage funds on behalf of the following philanthropic organizations:

The Simons Foundation’s mission is to advance the frontiers of research in mathematics and the basic sciences. Co-founded in New York City by Jim and Marilyn Simons, the foundation exists to support basic — or discovery-driven — scientific research, undertaken in pursuit of understanding the phenomena of our world.

To learn more, visit the Simons Foundation website.

The Heising-Simons Foundation works with its many partners to advance sustainable solutions in climate and clean energy, enable groundbreaking research in science, enhance the education of our youngest learners, and support human rights for all people. The foundation is based in Los Altos, California, and was established by Liz Simons and Mark Heising, who are joined on the board by their daughter, Caitlin Heising.

To learn more, visit the Heising-Simons Foundation website.

Foundation for a Just Society was founded by a group of women committed to advancing the human rights of women, girls, and LGBTI people around the world. It envisions a world without discrimination — where people are equally valued regardless of gender, race, ethnicity, economic status, or sexual orientation.

To learn more, visit the Foundation for a Just Society website.

Sea Change Foundation is a private family foundation established by Nat Simons and Laura Baxter-Simons. Sea Change is dedicated to achieving meaningful social impact through leveraged philanthropy that addresses the most pressing problems facing the world today. Since its inception in 2006, the Foundation’s focus has been addressing the serious threats posed by global climate change.

To learn more, visit the Sea Change Foundation website.