An arbitration clause included in contracts relating to investment services and activities entered into with investors is binding only on the intermediary, unless the intermediary proves that it was the result of direct negotiation within the meaning of Article 6 of Legislative Decree No. 179 of 8 October 2007; to that end, a mere reference in the preamble of the agreement to discussions and negotiations that took place does not discharge the burden of proof borne by the intermediary, it being necessary to demonstrate specifically the existence of direct, targeted negotiations that enabled the weaker contracting party to carry out a thorough assessment of the clause excluding ordinary jurisdiction.