Public financial intermediaries (PFIs) play a strategic role in many countries for their ability to finance large, long-maturity projects that generate positive externalities. This article proposes a framework for analyzing these actors that goes beyond their usual justification in terms of market failures. It then presents a historical analysis and an original typology of PFIs—absent from the existing literature—that reveals their diversity and their respective advantages in the face of the energy transition. Finally, it provides an initial assessment of the policies of the leading European PFIs in the face of climate change, before proposing recommendations for improving their action. JEL codes: G21, G28, Q01, Q48.