In Howsam v. Dean Witter Reynolds, Inc. (2002) 537 U.S. 79, the United States Supreme Court was asked to decide whether the court or an arbitrator should apply a National Association of Securities Dealers (NASD) rule that a dispute is not eligible for submission to arbitration after six years have elapsed from the event giving rise to the dispute. (Id. at p. 81.) The high court concluded there was a presumption that the arbitrator should decide "'allegations of waiver, delay, or a like defense to arbitrability.'" (Id. at p. 84) In reaching this conclusion, the Supreme Court explained that a "gateway dispute" about whether the parties are bound by a particular arbitration clause raised a "'question of arbitrability'" for a court to decide. (Id. at p. 84.) The NASD time limit rule, however, fell within a class of "gateway procedural disputes" not presenting such "'questions of arbitrability'" for the court. (Id. at p. 85.) The Court held that the application of a National Association of Securities Dealers ("NASD") rule imposing a time limit on submission of disputes for arbitration was a matter presumptively for the arbitrator, rather than the court, to decide. In reaching this determination, the Court distinguished between threshold issues of "substantive arbitrability which are for a court to decide," and those of issues of "procedural arbitrability," such as "time limits, notice, laches, estoppel, and other conditions precedent which are for the arbitrators to decide" (id. at 85). The category of substantive arbitrability includes disputes about "whether the parties are bound by a given arbitration clause" (id. at 84).