This document discusses how foundations can leverage their endowments to achieve both competitive returns and positive social impact through impact investing. It notes that traditionally foundations focused 95% of their endowments on retained investments and 5% on targeted grants, but impact investing allows them to "unleash the 95%" to generate social good. Impact investments can include assets like sustainable corporate bonds, community lending, affordable housing funds, clean technology funds, and microfinance funds. These investments allow foundations to meet financial return goals while also addressing social and environmental challenges. The document provides several examples of impact investment funds and themes that foundations could consider to align their missions with their investment strategies.