(154)Where the operation of a trading venue that has established arrangements in a host Member State has become of substantial importance for the functioning of the securities markets and the protection of the investors in that host Member State, the proportionate cooperation arrangements to be put in place should take the appropriate form amongst possible cooperation modalities between the competent authorities of the home and host Member States, proportionate to the needs for cross-border supervisory cooperation in particular resulting from the nature and scale of the impact on the securities markets and the investor protection in the host Member State, such as ad hoc or periodic information sharing, consultation and assistance.