In 2013, institutional investors in OECD countries (e.g. insurance companies, investment funds, pension funds, public pension reserve funds, foundations and endowments) held USD 93 trillion worth of assets (OECD, 2015c). Traditional sources of green infrastructure investments, such as governments and banks, face increasing constraints due to structural obstacles, deleveraging and impending financial regulations. In emerging and developing countries, sovereign wealth funds are key sources of capital, thanks to their USD 7 trillion in assets as of January 2015 (Sovereign Wealth Fund Institute, 2015).