Opinion of the Court
But Lamps Plus did not secure the relief it requested. It sought an order compelling individual arbitration. What it got was an order rejecting that relief and instead compelling arbitration on a classwide basis. We have explained—and will elaborate further below—that shifting from individual to class arbitration is a “fundamental” change, Stolt-Nielsen, 559 U. S., at 686, that “sacrifices the principal advantage of arbitration” and “greatly increases risks to defendants,” AT&T Mobility LLC v. Concepcion, 563 U. S. 333, 348, 350 (2011). Lamps Plus’s interest in avoiding those consequences gives it the “necessary personal stake in the appeal” required by our precedent. Camreta v. Greene, 563 U. S. 692, 702 (2011).[1]
III
The Ninth Circuit applied California contract law to conclude that the parties’ agreement was ambiguous on the availability of class arbitration. In California, an agreement is ambiguous “when it is capable of two or more constructions, both of which are reasonable.” 701 Fed. Appx., at 672 (quoting Powerine Oil Co. v. Superior Ct., 37 Cal. 4th 377, 390, 118 P. 3d 589, 598 (2005)). Following our normal practice, we defer to the Ninth Circuit’s interpretation and application of state law and thus accept that the agreement should be regarded as ambiguous. See, e. g., Expressions Hair Design v. Schneiderman, 581 U. S. ___, ___ (2017) (slip op., at 7).[2]
- ↑ And contrary to Varela’s contention, Brief for Respondent 14–15, and Justice Breyer’s dissent, post, at 6–7, this is hardly a case like Microsoft Corp. v. Baker, 582 U. S. ___ (2017). There, we held that plaintiffs cannot generate a final appealable order by voluntarily dismissing their claim. Here, Lamps Plus was the defendant, and the District Court compelled class arbitration over the company’s vigorous opposition.
- ↑ Justice Kagan offers her own interpretation of the contract, concludes that it unambiguously authorizes class arbitration, post, at 2–4, and criticizes us for “disregard[ing] the actual contract the parties
