The powers of arbitral tribunals are typically defined by the parties’ arbitration agreement, including the arbitral rules incorporated therein. However, interesting and often overlooked questions about the source and scope of the tribunal’s powers arise when it has yet to rule on the existence of an arbitration agreement, when it determines that no valid agreement exists, or after it renders a final award. In addition to these questions, this discussion will explore practical issues such as the enforceability of cost awards issued by a tribunal lacking jurisdiction on the merits, and recent case law regarding corrections and modifications to final awards.