Cooperation between financial supervisors in the European Union.

Summary Nowadays, cooperation between financial supervisors in the European Union is an apparent necessity. Indeed, the gradual harmonization of member states' legislation, the implementation of the European passport to facilitate the free movement of actors within the Union, the national competence based on the country of origin principle, as well as the mutual recognition of approvals and controls have made cooperation between member states' financial supervisors necessary. This necessity is a logical consequence of financial integration. On the one hand, the existence of common rules requires a consistent approach in their implementation across the European Union. On the other hand, the increasing scope of cross-border activities, together with the emergence of large financial institutions providing services in several business areas, requires close cooperation between financial supervisors. Indeed, in a cross-border and cross-sector context, cooperation is the main supervisory tool of financial supervisors. This process is in full mutation since the advent of the financial crisis. Thus, cooperation has been strengthened and centralized at the EU level since the establishment of the European Supervisory Authorities. Moreover, the centralization of supervision in the banking sector at the European level does not eliminate the need for cooperation, in particular because of the expertise of national authorities, their knowledge of national, regional and local banking markets, the significant resources they already have at their disposal, and geographic and linguistic considerations.