The two layers coexist, although with different responsibilities: the multinational nature of the Mechanism implies a multiplication of resources dedicated to the various tasks, also because of the need for coordination. It is a costly exercise. The “common roof” choice – A crucial decision was to place the SSM within the ECB.
It came after a prolonged discussion, where different lines of thought were confronting. The risk of a conflict of interest between monetary policy and supervisory action was meant to be mitigated by separating the analysis aimed at supervision from the one aimed at monetary policy, and analysis from decision-making.