The COVID-19 pandemic was an unprecedented exogenous shock for the European Union (EU) and its Member States, one that demanded a joint response at the EU level rather than several differentiated responses at the Member State level. As such, the pandemic crisis opened up a “window of opportunity” for institutional change in the EU’s financial assistance regime. This change pertains to the development of a set of rules governing the disbursement and withdrawal of funding to Member States in the context of crisis management. The paper thus aims to answer the following question: How did the COVID-19 pandemic affect the EU’s financial assistance regime? Drawing on a revisited historical institutionalist framework that allows for the examination of different types of institutional development, the paper argues that the COVID-19 pandemic constitutes a “critical juncture” for the EU's financial assistance regime, resulting in a shift from intergovernmental coordination (with the European Stability Mechanism) to a form of limited supranational delegation (with the Recovery and Resilience Facility).