Global demand for sustainable development finance exceeds available public funding many times over, placing increasing expectations on the GEF to attract private capital for global environmental benefits. Early GEF investments focused on climate change mitigation areas, including renewable energy and energy efficiency. More recently, the GEF has ventured into environmental and nature related sectors, such as biodiversity and land management. This STAP Information Note provides a short review of the academic and practitioner literature and describes a few case studies of GEF blended finance projects. Drawing from the literature, case studies, and observations from project screening, STAP highlights the potential for a more systematic classification of types of interventions to create GEBs and the contexts in which they are applied to help identify those most amenable to different blended finance instruments. The Note identifies four issues to frame an agenda for further investigation.