The Single Supervisory Mechanism transferred to the European Central Bank (ECB) powers of prudential supervision over the main credit institutions operating in the Eurozone. However, the end of State monopoly over such supervision did not also end intervention by national authorities. Rather, this interventions has simply changed form. Today, the effort to coordinate with domestic central banks has become a crucial issue. This article examines the various morphologies of coordination and divides them into four categories, comparing them with those of the Single Resolution Mechanism. Generally, the existence of multiple controllers produces a weak system, from which operators may benefit by using conflict regulation to their advantage. In the realm of banking supervision, studies adopting an empirical approach have shown that the ECB cannot exercise this function exclusively, also due to the genetic characteristics of European administrative law. By operating in accordance with a single authority model mitigated by stable coordination mechanisms, the ECB acts as a guarantor for the balance between the decentralization of duties at national level with the need for unity within European
regulation.