Adding To The Tally: Another Court Denies Bid For Class Certification In Cookie Tracking Case

On July 20, 2026, another California federal court denied class certification in a putative privacy class action involving a company’s cookie-based advertising platform. Lewis v. Magnite, Inc., 2:25-cv-03448-MWC-SSC (C.D. Cal. July 20, 2026). The plaintiffs alleged that Magnite secretly installed tracking cookies—called “khaos IDs”—on users’ browsers to collect data for targeted advertising. The claims included violations of the federal Wiretap Act (ECPA) and California Invasion of Privacy Act (CIPA), among other privacy-based claims.

Why the Court Said “No” to Class Certification

The court found multiple fatal flaws in the plaintiffs’ certification bid:

• Individualized consent issues. Because putative class members visited different websites with different privacy policies and cookie disclosures, each person’s consent (or lack thereof) required individual analysis. The court noted that determining what each user saw, agreed to, and understood would overwhelm any common