In its January 14, 2014 decision in Mississippi v. AU Optronics Corp., the US Supreme Court resolved a circuit court split by holding that a suit filed by a state government as the sole plaintiff on behalf of its citizens did not constitute a mass action under the Class Action Fairness Act (CAFA) (No. 12-1036, (S. Ct. Jan. 14, 2014)).

The state of Mississippi brought suit in state court against LCD manufacturers on behalf of its citizens, alleging that the manufacturers restricted competition and fixed prices in the LCD market. The manufacturers removed the case to federal court under CAFA, on the grounds that the case was either a class action (brought under FRCP 23) or a mass action (involving monetary relief claims of "100 or more persons" who are proposed to be tried jointly on the ground that their claims involve common questions of law or fact). The state filed a motion to remand. The district court ruled that the suit did not qualify as a class action but constituted a mass action, and remanded the case to state court on the basis of CAFA's general public exception, which excludes claims asserted on behalf of the general public from the mass action definition.

The US Court of Appeals for the Fifth Circuit reversed, finding that while the suit qualified as a mass action, the case did not fall within the general public exception.

The Supreme Court reversed the Fifth Circuit and held that the suit did not constitute a mass action under CAFA because Mississippi was the only named plaintiff. Removal to federal court was therefore inappropriate. The unanimous court disagreed with the notion that there may be 100 or more unnamed persons who are real parties in interest as beneficiaries to the plaintiffs' claims in a suit brought by fewer than 100 named plaintiffs.

The court looked to the plain language of the statute and found that Congress intentionally excluded unnamed persons from the definition of mass action. Notably, the provision refers to the "100 or more persons" as "plaintiffs," which is consistently used under CAFA to refer to actual named parties rather than unnamed real parties in interest. The court further noted that to stretch "plaintiffs" to include all unnamed individuals would make determining jurisdiction over plaintiffs whose claims exceed $75,000 unwieldy and an "administrative nightmare."

Additionally, the court concluded that federal courts may not look beyond the pleadings to the substance of the action when considering mass action pleadings.