The «from billions to trillions» slogan, calling for the mobilization of trillions of dollars in private capital for sustainable development, has inspired the derisking policies of development banks. Its quantitative failure is not that of derisking itself — a concept potentially carrying a new form, demanding but promising, of public-private partnership. This paper reviews the rationale for derisking, its historical and theoretical foundations, its role in bringing private returns closer to societal returns, and the conditions that can make it effective.
