By Gerald L. Maatman, Jamar D. Davis, and Caitlin Capriotti
Duane Morris Takeaways: On April 1, 2026, in Laura O’Dell et. al. v. Aya Healthcare Services, Inc., No. 25-1528, 2026 U.S. App. LEXIS 9420 (9th Cir. Apr. 1, 2026), a panel for the Ninth Circuit held that the U.S. District Court for the Southern District of California erred in relying on non-mutual offensive collateral estoppel to preclude the enforcement of hundreds of arbitration agreements based select arbitral awards from unappointed arbitrators for different parties. This decision reaffirms the principle of consent set forth in the Federal Arbitration Act (“FAA”) and the Ninth Circuit’s preference (in line with the FAA) for enforcement of valid arbitration agreements in individualized proceedings.
Case Background
Aya Healthcare Services, Inc. (“Aya”) is an agency the pairs traveling nurses and other supporting clinicians with hospitals in need. In 2022, four former employees filed a putative class action against Aya for allegedly reducing their pay mid-contract, asserting breach of contract, fraudulent inducement, state wage-and-hour violations, and violations under the Fair Labor Standards Act (FLSA). As a condition of employment, all employees signed arbitration agreements to resolve any employment-related disputes outside of the court system. Aya moved to compel arbitration, and the U. S. District Court for the Southern District of California (the “District Court”) granted the motion and compelled all four named plaintiffs to arbitration.
Aya proceeded to arbitrate with each of the four plaintiffs in four separate arbitrations. Each plaintiff challenged the validity of the arbitration agreements, and the delegation clause assigned the arbitrator (rather than the court) authority to decide whether the arbitration agreement was valid. Two arbitrators ruled the arbitration agreements were unconscionable, and two arbitrators ruled the arbitration agreements were valid. By the time the parties moved the District Court to confirm their respective arbitral awards, 255 additional plaintiffs had opted-in to the case pursuant to a collective action procedure under the FLSA. Aya moved to compel each of these plaintiffs to arbitration. In response, a newly assigned district judge raised sua sponte the issue of whether collateral estoppel barred Aya from enforcing the additional arbitration agreements against the opt-in plaintiffs. Ultimately, the District Court denied Aya’s motion to compel arbitration.
The District Court applied the doctrine of non-mutual offensive collateral estoppel to preclude the enforcement of the arbitration agreements between Aya and the 255 employees. This doctrine was “non-mutual” because a party different from the party in the original action is seeking preclusion and “offensive” because the new party is using a prior award as a sword (rather than a shield). However, the District Court only gave the collateral estoppel effect to the two decisions finding the arbitration agreements unconscionable, and awarded no such power to the decisions holding the arbitration agreements as valid. The Ninth Circuit reviewed the motion to compel arbitration de novo.
The Ninth Circuit’s Decision
The Ninth Circuit held that the District Court’s novel application of an equitable preclusion doctrine did not preclude the enforcement of the arbitration agreements because application of the doctrine runs contrary to FAA’s intention to enforce the agreed upon terms of valid arbitration agreements in individualized proceedings. “Precluding an arbitration that the parties had agreed to – because a different arbitrator in a different proceeding had concluded that an agreement between different parties was unconscionable – would render the parties’ consent meaningless,” wrote U.S. Circuit Judge Eric C. Tung (emphasis in original). This goes against the fundamental requirement that each arbitration agreement requires individualized resolution. The Ninth Circuit also stated that “the application of non-mutual offensive issue preclusion would also violate the principle of consent that the [Federal Arbitration Act (“FAA”)] incorporates.” Id. at *8. When parties enter arbitration agreements, the FAA serves to have those agreements enforced. Further, even when the validity of an arbitration agreement is at issue, the issue-preclusion doctrine is not a “generally applicable contract defense.” Id.
Further, the Ninth Circuit determined that the District Court’s order effectively transformed individual arbitration proceedings into a bellwether class action to which the parties never agreed. This also goes to the issue of consent. The Ninth Circuit cited the U.S. Supreme Court’s decisions in Epic Systems Corp. v. Lewis, 584 U.S. 497 (2018), and Stolt-Nielsen S.A. v. AnimalFeeds Int’l Corp., 559 U.S. 662 (2010), as holding that imposing a class action without the parties’ consent (or adequacy of representation) and where the parties had agreed to individual arbitration is a violation of the FAA. Allowing one arbitration proceeding to preclude hundreds or thousands of arbitration agreements, as the logic of the District Court suggests, regardless of adequacy of representation, would strip the resulting class action from all its important protective features.
As a result, the Ninth Circuit reversed the District Court’s judgment and remanded for further proceedings.
Implications For Employers
This decision reaffirms the strength of the FAA and reiterates the Ninth Circuit’s preference for enforcing arbitration agreements on an individualized basis.
District court judges who may have personal preferences against arbitration cannot destroy the FAA with novel doctrines inconsistent with the FAA.










