Starting with a discussion of a recent court judgment on the prudential supervisory powers of the European Central bank (ECB), the L-Bank judgment of 16 May 2017 in Case T-122/15 (currently under appeal: Case C-450/17 P), this paper explores the development of the Single Supervisory Mechanism (SSM) and of the Eurosystem, as two formations of the ECB acting together with national authorities. The allocation of powers in both systems is analysed on the basis of the administrative and judicial reviewability of acts of the central banks and supervisory authorities; ‘intersection issues’ between national and Union competences in supervision; the role of national law in supervision and the national implementation of EU directives in the area of prudential supervision; and the measure of ‘Europeanisation’ of competences in respect of the holding of gold reserves and the provision of liquidity to banks (lender of last resort). A brief foray into the different supervisory liability regimes for the ECB and selected national supervisory authorities precedes concluding suggestions for further study and development of Europe’s Economic and Monetary Union (EMU).

The ADEMU Working Paper Series is being supported by the European Commission Horizon 2020 European Union funding for Research & Innovation, grant agreement No 649396.