Proposals for common European Union debt have resurfaced, driven by two distinct rationales: financing specific European public goods, and expanding the share of EU debt to deliver broader macroeconomic benefits. This paper focuses on the second rationale, examining whether current and proposed institutional arrangements can deliver the benefits their proponents claim. We find that the full set of these benefits, which include lower public borrowing costs, improved financial stability and deeper capital market integration, would only materialise under a fiscal union, in which the EU’s fiscal powers are comparable to those of a federal government […]