In Argentine Republic v National Grid PLC, (D.C. Cir. Mar. 11, 2011), Argentina and National Grid participated in an arbitration pursuant to the bilateral investment treaty (BIT) between the UK and Argentina. The arbitral panel found that Argentina violated the BIT and was liable to National Grid. Argentina received a copy of this award on 13 November 2008. Under the Federal Arbitration Act (FAA), Argentina had three months to file and serve notice of a motion to vacate or modify the award.

Argentina filed a motion to vacate the award in District Court on 6 February 2009. It then filed a motion to extend time to serve notice on 10 February 2009. FRCP 6(b) allows courts to extend the time to file a motion for "good cause." Argentina argued that it was impossible to complete service on a company in the UK as required by the Hague Convention within the three-month period allowed by the FAA.

After Argentina and National Grid filed a joint stipulation stating that National Grid would accept service of process but not waive any defences, the District Court dismissed the motion to extend as moot and denied the motion to vacate the arbitral award as untimely. It also granted National Grid's cross-motion to confirm the award.

Argentina appealed, arguing that the District Court incorrectly found its motion to extend moot. National Grid replied that Rule 6(b) cannot be used to extend time periods imposed by statutes, rather than by the court or court rules. The DC Circuit rejected Argentina's position and held that Rule 6(b) could not be used to extend statutory time periods. It noted that every court to address this question has held that Rule 6(b) may not be used to extend statutory time limits.

This case serves as an important reminder to parties seeking to modify or vacate arbitral awards that time periods provided by the FAA cannot be extended.