علی اصغر رحیمی

Independence and impartiality are essential indicators for qualified arbitrators. However, the criteria for assessing these indicators differ among competent authorities when addressing challenges to arbitrators. One contentious aspect is the nationality of the arbitrators. By examining arbitration rules and issued decisions, a distinction was made between commercial arbitration and investment arbitration. The ICSID rules of arbitration explicitly mention common nationality with the parties as a criterion for challenging an arbitrator. The ICSID practice has also influenced investment arbitration outside of ICSID, given the significant role of nationality throughout investment law. Conversely, in commercial arbitration, the role of nationality is less pronounced, to the extent that the international character of arbitration in various legal systems is determined by the differences in the parties' places of business rather than their nationalities. Consequently, the nationality of arbitrators in commercial arbitration cannot solely serve as a basis for challenging an arbitrator without other supporting factors.