(4)Although NCAs are primarily responsible for exercising the relevant options and discretions in relation to less significant institutions, the ECB’s overarching oversight role within the SSM enables it to promote the consistent exercise of options and discretions in relation to both significant and less significant institutions, where appropriate. This ensures that: (a) the prudential supervision of all credit institutions in the participating Member States is implemented in a coherent and effective manner; (b) the single rulebook for financial services is applied consistently to all credit institutions in the participating Member States; and (c) that all credit institutions are subject to supervision of the highest quality.