(12)However, a regulatory regime which entails too much uncertainty for investment firms may reduce efficiency. Competent authorities are expected to issue interpretative guidance on provisions on this Directive, with a view in particular to clarifying the practical application of the requirements of this Directive to particular kinds of firms and circumstances. Non-binding guidance of this kind might, among other things, clarify how the provisions of this Directive and Directive 2004/39/EC apply in the light of market developments. To ensure a uniform application of this Directive and Directive 2004/39/EC, the Commission may issue guidance by way of interpretative communications or other means. Furthermore, the Committee of European Securities Regulators may issue guidance in order to secure convergent application of this Directive and Directive 2004/39/EC by competent authorities.