(66)If employees have participation rights in one of the merging companies under the circumstances set out in this Directive and, if the national law of the Member State in which the company resulting from the cross-border merger has its registered office does not provide for the same level of participation as operated in the relevant merging companies, including in committees of the supervisory board that have decision-making powers, or does not provide for the same entitlement to exercise rights for employees of establishments resulting from the cross-border merger, the participation of employees in the company resulting from the cross-border merger and their involvement in the definition of such rights should be regulated. To that end, the principles and procedures provided for in Council Regulation (EC) No 2157/2001 ( 21 ) and in Council Directive 2001/86/EC ( 22 ) , should be taken as a basis, subject, however, to modifications that are deemed necessary because the resulting company will be subject to the national laws of the Member State where it has its registered office. A prompt start to negotiations under Article 133 of this Directive, with a view to not unnecessarily delaying mergers, may be ensured by Member States in accordance with Article 3(2)(b) of Directive 2001/86/EC.