Abstract: Private sector development is a model of international development that uses official development assistance to invest directly in the private sector enterprises in developing states. Since 2000s, many development finance institutions (DFIs) had been created, mostly in Europe and North America, to promote private sector development in the Global South. Belgian Investment Company for Developing States (BIO) is one such European DFI, investing in the private sector, as part of the Belgian Development Cooperation. In this study, which was commissioned by a group of Belgian civil society organisations, the authors examine BIO’s business model, environmental and social (E&S) commitments, accountability, and investment portfolio in agri-food and climate finance. This is the first in-depth study of this kind that analyses BIO’s legal and institutional framework, together with a sample of BIO’s direct and indirect investments, building on restricted data shared by BIO, and on interviews with BIO and its stakeholders.