Article 83
A competent authority may refuse to act on a request for cooperation in carrying out an investigation, on-the-spot verification or supervisory activity as provided for in Article 84 or to exchange information as provided for in Article 81 only where:
(a)
judicial proceedings have already been initiated in respect of the same actions and the same persons before the authorities of the Member State addressed;
(b)
final judgment has already been delivered in the Member State addressed in respect of the same persons and the same actions.
In the case of such a refusal, the competent authority shall notify the requesting competent authority and ESMA accordingly, providing as detailed information as possible.