A federal judge in Seattle dismissed a proposed class action against Costco Wholesale on October 16, 2026, declining to adjudicate claims that its Kirkland Signature tequila was falsely labeled as 100% agave. The court cited international comity and the act of state doctrine, deferring to Mexico’s regulatory authority over tequila.
The lawsuit, filed in November 2025 by the firm Hagens Berman, involved fourteen plaintiffs from nine states. They alleged that Costco’s Kirkland Signature line, including Blanco, Reposado, Añejo, Cristalino, and Extra Añejo, was sold under “100% de Agave” and “100% Agave Azul” labels while containing substantial amounts of alcohol derived from non-agave sources. The complaint cited private SNIF-NMR testing of certain samples that, according to the plaintiffs, showed the Blanco containing roughly 60 to 80% agave-derived ethanol and the Reposado as little as 5 to 25%. They asserted claims under the federal Racketeer Influenced and Corrupt Organizations Act and various state consumer protection statutes. Costco denied the allegations and argued that the products had been certified under Mexican standards.
Judge Kymberly K. Evanson of the U.S. District Court for the Western District of Washington agreed that deciding the claims would require a U.S. court to reexamine Mexico’s regulatory determinations. Tequila is a protected designation of origin governed by the official Mexican standard NOM-006. Mexican authorities, including the Dirección General de Normas and the Fiscalía General de la República, had already reviewed similar allegations of adulteration. Those proceedings rejected the private testing methods as insufficient to demonstrate non-compliance, relying in part on analyses from the Consejo Regulador del Tequila. The court concluded that the relief sought would effectively challenge those official acts.
The ruling does not include any independent finding on the composition of the Kirkland products. It holds only that the dispute, as framed, falls outside the proper scope of a U.S. court under the doctrines of international comity and the act of state. Plaintiffs’ counsel Steve Berman said the decision was incorrect and indicated that an appeal would be filed.
Under Mexican law, tequila labeled “100% de Agave” must derive its fermentable sugars entirely from blue Weber agave. Other tequila may contain at least 51% agave-derived sugars, with the remainder coming from permitted non-agave sources. The distinction is central to the allegations, which challenge whether the Kirkland products complied with the stricter designation.
The case is one of several U.S. lawsuits challenging “100% agave” labeling. Earlier in October 2026, a federal judge in New York dismissed a proposed class action against Diageo concerning Don Julio and Casamigos. That court cited the limited number of samples tested and difficulties connecting the results to the plaintiffs’ purchases. The Costco dismissal, by contrast, turned on deference to Mexican regulatory proceedings rather than the sufficiency of the evidence presented. Other actions involving brands such as 818, Cincoro, Lunazul, and Teremana remain pending at varying stages.
Kirkland Signature tequila is produced for Costco by third-party distilleries in Jalisco, with the specific facility indicated by the NOM number on each bottle. The ruling underscores the importance of Mexico’s regulatory and certification framework in disputes over tequila labeling in the United States. Whether the decision will influence similar cases involving other brands remains to be seen, particularly if the plaintiffs appeal.
