The participants in the Single Supervisory Mechanism (SSM) are all the countries that form part of the Eurosystem and all European Union countries which are not in the euro area, but which want to establish close cooperation with the European Central Bank (ECB) and therefore accept this supervisory system.
The ECB directly supervises institutions considered to be significant, while all other less-significant institutions are directly supervised by national competent authorities (NCAs), and indirectly supervised by the ECB.
The criteria for determining whether an institution is significant are:
- The total value of its consolidated assets exceeds €30 billion.
- The value of its assets exceeds 20% of the GDP of the country in which it is established, unless the total value of its consolidated assets is below €5 billion.
- It is one of the three most significant credit institutions in a Member State.
- It has subsidiaries in more than one participating country, and the ratio of its cross-border assets or liabilities to its total assets or liabilities is above 20%.
- It has requested or received direct financial assistance from the European Financial Stability Facility or the European Stability Mechanism.
On its banking supervision website, the ECB publishes a list of significant institutions, which is periodically updated based on these criteria.