What it is
The Single Supervisory Mechanism (SSM) is the first pillar of the Banking Union and the body of prudential supervision for banks in participating Member States. It brings together the European Central Bank and the national competent authorities of those states into a single system with the ECB at its centre. The purpose is to apply supervisory standards consistently across borders, to break the reliance on purely national judgment that failed during the crisis, and to give the resolution framework a common supervisory counterpart.
Supervision under the SSM is divided by significance. The ECB directly supervises the banks classified as significant institutions — measured chiefly by size, cross-border activity and economic importance — while less significant institutions are supervised by their national competent authorities within the ECB's oversight and common methodologies. The ECB can also take over direct supervision of any bank where necessary to ensure consistent standards. Certain tasks, such as authorising and withdrawing banking licences and assessing qualifying holdings, are reserved to the ECB across all banks in the system.
How it relates to resolution
The SSM is the supervisory half of the crisis-management framework; the Single Resolution Mechanism is the resolution half. The two are deliberately kept distinct: the competent authority supervises the going-concern bank, sets Pillar 2 requirements, runs the supervisory review and evaluation process, and can impose early-intervention measures when a bank deteriorates. When supervision can no longer keep a bank viable, it is the supervisor — the ECB for significant institutions — that normally determines the bank is failing or likely to fail, in consultation with the resolution authority. That determination is the trigger that hands the case to the resolution side. Keeping supervision and resolution in separate hands guards against the conflict of interest that would arise if the same body both nursed a bank and decided its resolution.
Legal basis
The SSM is established by the SSM Regulation, Council Regulation (EU) 1024/2013, which confers specific supervisory tasks on the ECB. Article 6 sets out the cooperation between the ECB and national competent authorities and the division of tasks between them, with the ECB responsible for the direct supervision of significant institutions. The substantive prudential rules the SSM enforces are those of the Capital Requirements Regulation and Directive. The European Banking Authority remains the standard-setter for the single rulebook that applies across the whole EU, including the states inside the SSM.
Practical relevance for banks and investors
For a bank, its classification as significant or less significant determines whether the ECB or its national authority is its day-to-day supervisor, and therefore who sets its capital add-ons and reviews its risk. For investors, the SSM offers a degree of supervisory consistency across the participating states and a clearer line between the authority that supervises a bank and the authority that would resolve it. The point at which a supervisor concludes a bank is failing or likely to fail is the hinge between the two regimes.