In case of interpretative doubt as to the institutional or contractual nature (arbitrato irrituale) of an arbitration clause contained in articles of association, the court must favour the qualification of the arbitration as institutional.
The plea of institutional arbitration, being in the nature of a plea of lack of jurisdiction, is subject to the time limits provided for the timely entry of appearance of the defendant, with the consequence that late entry of appearance results in the loss of the right to rely on the arbitration clause.