Looking through the lens of the practices before the International Chamber of Commerce and the International Centre for International Dispute Settlement, the paper aims to provide an overview of the factors determining the way in, and the style with which arbitral tribunals in commercial and investment international arbitration ground their awards. For this purpose, the paper reviews the literature on the topic, examining the extent to which, before ICC and ICSID tribunals, the need to satisfy parties’ expectations and demand for justice influences the arbitrators’ choices regarding reasons for their decisions. The paper also verifies, through scholarly analysis, the impact the specific features of international arbitration (such as the arbitrators’ being private judges appointed by the parties to the dispute, and the award’s enforcement being subject to positive scrutiny by national courts) have on the reasoning requirement. Finally, the paper investigates how, and to what extent, a different set of elements – namely, the subject matter of the decision, the degree of publicity of the award, the size of its expected readership, and the cultural milieu(s) to which the arbitrators belong – shape the reasoning of arbitral tribunals constituted under ICC and ICSID rules.
