O’Melveny represented Chemtura Corporation on multiple state and federal appellate and defensive fronts, including five separate federal multi-district litigation matters alleging conspiracies involving different products during separate time periods. In Sperry v. Crompton Corp., plaintiffs sought to certify a devastatingly large class―all consumers who purchased tires that were manufactured using rubber-processing chemicals sold since 1994. They alleged antitrust violations and unjust enrichment, and sought treble damages under the Donnelly Act, an antitrust statute in New York. In a landmark decision, the O’Melveny team successfully obtained dismissal of the state antitrust claims by persuading the state’s highest court to hold that the Donnelly Act does not authorize class-action lawsuits. The opinion was unanimous. This case was closely watched by many groups. The United States Chamber of Commerce filed an amicus brief in support of Chemtura and other defendants. Then- New York Attorney General Elliott Spitzer, the American Antitrust Institute, and AARP filed amicus briefs in support of Sperry. Global Competition Review referred to the Sperry victory as a “landmark” result.