This chapter focuses on banking supervision and enforcement in the EU. With the entry into force of the Single Supervisory Mechanism (SSM) Regulation, this sector is a prime example of where the verticalisation of EU law enforcement has occurred. It analyses the main aspects of the new supervisory system, particularly the division of tasks and powers between the European Central Bank and two national competent authorities, De Nederlandsche Bank and the Bank of Greece. Then it considers to what extent mechanisms relating to political accountability keep checks and balances under control and discusses redundancies and gaps in the system of judicial accountability. It concludes that while the system is generally robust, confidentiality obligations, as well as the ambiguous nature of instructions, may be placing certain limits on political and judicial accountability.