The EBU represents a clear investment in administrative integration with clear implications for the constitutional features of the EU. This paper aims to give an analysis of the administrative arrangements, through which the functions of supervision and resolution are affecting the single financial market. This case study is very interesting because these functions represent a genuine novelty in the history of financial integration since they are pre-ordained to a specific public interest: financial stability. Particularly, they cause a shift in the decision gradient from the technical to the political, as market integrity is less and less the key interest compared to financial stability. However, this wider discretionary power is not adequately counteracted by checks and balances in favour of accountability. As a result, the EBU makes a new contribution to the well-known ‘fragmentation of the executive power’ of the EU by introducing a new governance tool positioned between the Communitarian and Intergovernmental Method, but its development is still full of uncertainties given that constitutional equilibrium is far from being definitively reached.