Such aspects as the powers of supervisory authorities over market entry and exit, intermediaries’ governance and internal controls, and sanctions affect each nation’s normative and institutional arrangements more substantially and so require specific national rules for implementation. These parts of the rulebook may well continue to be governed at Community level by the traditional instrument of the directive, albeit one for maximum harmonization.
6  BIS Review 119/2009  (iii)  Convergence on a high level of prudential rigour in standards and application. Finally, turning to the substance of the single rulebook, it is important that convergence not be pursued at the expense of the efficacy of rules and controls.