A single set of harmonised prudential rules for all banks in the European Union would not, in and of itself, be sufficient for the EU to be considered as a single geographical area.
But the Single Rulebook, the existence of a single supervisor, the Single Supervisory Mechanism (SSM), of a single resolution authority, the Single Resolution Mechanism (SRM), and of a common backstop, the Single Resolution Fund (SRF), when taken together, have equipped the banking union with all the features of a single geographical area.