The chapter discusses enforcement aspects of the European Banking Union. The Single Supervisory Mechanism and the Single Resolution Mechanism are based on a far-reaching composite administration whereby the EU and national authorities and legal orders are in constant interaction. It is argued that the centralization of tasks and responsibilities at the EU level and the bringing together of national expertise, experience and knowledge generally succeeds in rebuilding public trust in the banking system. At the same time, it is posited that such extensive mixed administration results in many challenges for ensuring an effective enforcement of the relevant EU laws. The chapter then highlights a number of open questions that are worth being further researched.