It ensures that a level playing field for financial institutions will be established through a single rulebook, thus avoiding regulatory arbitrage and distortions to competition. Furthermore, the harmonised rules also support financial integration and improve transparency. Finally, this approach also reduces regulatory costs as well as banks’ compliance costs.
Given the substantial benefits of greater financial  BIS central bankers’ speeches  5  integration, the ECB has consistently supported the “single rulebook” approach for financial regulation, with the aim of promoting the smooth functioning of the Single Market.