Building a European Union ‘Treasury’: Explaining the European Commission's New Approach to Debt Issuance and Management

Abstract This article examines how the European Commission went from being an occasional participant in capital markets in the 1970s to an established bond issuer by the 2020s. As a result of these changes, the Commission has moved away from its traditional model of back‐to‐back lending using a wide array of funding instruments towards the regular issuance of EU bonds and bills in the style of a European treasury. Using a principal–agent approach, we ask whether this shift was driven by member states seeking to reap the benefits of collective borrowing or rather by slippage by the Commission aimed at spurring European integration. Our results show that the Commission's occasional attempts to advance wider political objectives were rebuffed by member states, which, nonetheless, ultimately embraced the idea of a European treasury. Our findings emphasise the logic of delegation over agency slack when it comes to the EU's evolution as a borrower.