Arbitrators, as adjudicators of commercial disputes, have circumscribed authority. They are retained by the parties to resolve their disputes and for no other purpose. The doctrine of functus officio (that is, having performed the office) holds that once an arbitrator renders a decision regarding the issues submitted, in the form of an award, he or she lacks any power to reexamine that decision. In most instances, functus officio prevents further action by the tribunal, meaning that the parties—to their dismay, or delight, depending on their position in the case—are stuck with the award, even when the arbitrators have acknowledged the award contained an error and would like to correct it. A recent Second Circuit decision, however, shows that this doctrine is not necessarily as limited as many may believe. See Smarter Tools v. Chongqing SENCI Import & Export Trade, 57 F. 4th 372 (2d Cir. 2023).

The first source for allowable changes to arbitral awards is institutional rules. The rules of most major arbitral institutions allow for "computational, clerical or typographical" errors to be corrected by the arbitrators on their own initiative, or at the request of the parties (always within stated time limits). See, for example, International Chamber of Commerce (ICC), Article 36; ICDR Article 36. The rules of many institutions also permit arbitrators to make additional awards—sometimes on their own initiative and sometimes only at the request of a party—as to any claim, counterclaim or cross-claim presented in the arbitration but not decided in the award. See, for example, LCIA Article 27; SIAC Rule 33.