Of the multilateral climate funds, the GCF has the strongest private sector focus and houses a private sector facility that enables it to finance directly and indirectly at the national, regional and international levels. This evidence review summarises causal evidence presented in existing systematic reviews on four key market-based approaches: payments for environmental services, willingness-to-pay assessments, insurance products and results-based payment modalities. The approach paper details the theory of change used, the methods, search strategy, data collection and analysis procedures.