Originally from European International Arbitration Review (EIAR)

Once appointed, an arbitrator does not become a party to the arbitration clause—which would transform it into a trilateral agreement including the parties and the arbitrator(s)1—but rather to a contract with the parties and, as the case may be, the institution administering the arbitration. In an ad hoc arbitration the contract—generally known as receptum arbitrii2—is between the parties and the arbitrator(s). While appointed by one party, the party appointed arbitrator is contractually committed to both. If an institution is involved, it is contractually empowered to perform the tasks described in its arbitration rules, such as appointing, confirming, removing arbitrators, administering the arbitration, notifying the award, etc.

The contract is concluded in a variety of ways: by simple acceptance of the arbitrator(s) upon written request from the parties in a text containing the arbitrator’s mission would be the simplest form but this rarely occurs3 and generally the process involves each party appointing “its” arbitrator, subject to a formal acceptance of the offer to act as arbitrator, with the party appointed arbitrators and/or the institution proposing or nominating the chairman. The contract is generally regarded as governed by the law of the seat of the arbitration.4 Some other solutions, such as the law of the arbitrator’s domicile at the time of acceptance, could be considered in theory but not without some practical difficulties, considering that the arbitrator’s appointment, powers and removal largely depend on the arbitration law of the seat.

The legal nature of the arbitrator’s contract is quite clear in Swiss law:5 the receptum arbitrii is a special type of mandate within the meaning of art.394ff CO6 but one to which almost all provisions of this contractual pattern in the CO do not apply. Indeed an arbitrator is not the agent of the party that appointed him; he does not receive instructions; the party appointing the arbitrator cannot terminate the contract at will as it would in a normal mandate and neither can the arbitrator resign. Similar views appear to prevail almost everywhere.7