On January 14, 2014, the Supreme Court decided Mississippi v. AU Optronics Corp., No. 12-1036, holding that a suit filed by a State as the sole plaintiff does not constitute a "mass action" under the Class Action Fairness Act of 2005 (CAFA) even though it includes a claim for restitution for injuries suffered by the State's citizens.

The State of Mississippi sued certain manufacturers of liquid crystal displays (LCDs) in state court, alleging that the companies had formed an international cartel to raise prices and restrict competition. The State claimed violations of the Mississippi Antitrust Act and the Mississippi Consumer Protection Act. It sought injunctive relief, civil penalties, punitive damages, costs, attorney's fees, and restitution for its own purchases of LCD products and the purchases of its citizens. The manufacturers filed a notice to remove to federal court, arguing that the case was removable as either a "class action" or a "mass action" under CAFA.

The district court found that the suit did not qualify as a "class action" but did qualify as a "mass action" because it involved more than 100 unidentified Mississippi consumers as real parties in interest to the State's restitution claim even though the State was the only named plaintiff. The district court nonetheless remanded the case to state court because of CAFA's "general public exception," which excludes from the definition of "mass action" claims asserted on behalf of the general public under state statutes authorizing such claims. 28 U.S.C. § 1332(d)(11)(B)(ii)(III). The Court of Appeals reversed. It agreed with the district court that the action did not qualify as a "class action" but did qualify as a "mass action"; it found, however, that the "general public exception" did not apply, and therefore deemed the action removable.

The Supreme Court reversed. It noted that CAFA defines "mass action" as "any civil action (except a [class action]) in which monetary relief claims of 100 or more persons are proposed to be tried jointly on the ground that the plaintiffs' claims involve common questions of law or fact." §1332(d)(11)(B)(i). The Court determined that the reference to "100 or more persons" should be construed as a reference to 100 or more named plaintiffs and does not include unnamed real parties in interest.

The manufacturers' argument that "persons" should be read to include unnamed parties in interest did not square with the specific references to "plaintiffs" elsewhere in the definition of mass action and would require unwieldy judicial inquiries to satisfy the requirement that federal jurisdiction in mass actions exists only over those plaintiffs whose claims exceed $75,000. The Court found its reading of the text reinforced by the statutory context and rejected the argument that Congress intended the courts to make a real party in interest inquiry. Because Mississippi is the only named party in this action, the case does not qualify as a mass action.

Justice Sotomayor delivered the opinion for a unanimous Court.