On August 4, 2026, the American Antitrust Institute (AAI) filed an amicus brief in United States v. Google LLC, No. 26-5023, asking the D.C. Circuit to affirm the district court’s finding that Google unlawfully maintained its search monopoly but remand the remedial order with instructions to prohibit Google’s payment-for-default mechanism, which the district court’s liability opinion condemned but its remedy opinion left in place.
After a nine-week bench trial, the district court found that Google entered revenue-sharing arrangements with browser makers, device manufacturers, and other search access points, conditioning those payments on Google’s status as the distributor’s exclusive default search engine. The court found that these arrangements foreclosed a substantial share of the market, prevented rivals from gaining scale, and diminished rivals’ incentives to invest and innovate. It entered equitable relief that, among other things, imposed data and syndication remedies but permitted Google to continue paying for default placement. On appeal, Google argues, among other things, that its conduct was not exclusionary but rather competition on the merits, contending that plaintiffs must show that a rival would have won default placement in a counterfactual world without Google’s payments.
AAI’s brief argues that the district court committed no error in finding liability but erred in fashioning the remedy. On liability, AAI explains that Google’s proposed “but-for world” exclusionary-conduct standard—which would require plaintiffs to prove that a rival would have obtained default status absent Google’s payments—has no basis in Supreme Court or D.C. Circuit precedent and would defeat the consumer-welfare purpose of Section 2. The standard contravenes Microsoft, which declined to condition a finding of exclusionary conduct on proof that rivals would have prevailed in a counterfactual market, and it systematically warps the balance of error costs by effectively immunizing the most entrenched monopolists, whose conduct makes counterfactual reconstruction impossible. A monopolist that pays distributors out of its monopoly profits to foreclose rivals—rather than competing on the merits of its product—is engaged in precisely the conduct antitrust law is designed to prevent.
On the remedy, AAI argues that while the district court’s data and syndication remedies should be affirmed, the court erred by permitting Google to continue paying for default placement, the very bargain its liability opinion condemned. Antitrust remedial discretion, although broad, is bounded by a non-negotiable effectiveness requirement: relief must reach the whole of the violation. By preserving the payment-for-default mechanism while acknowledging that doing so “could blunt the effectiveness of the remedies imposed,” the district court allowed a consideration governing the choice among effective remedies to excuse its failure to impose one.
The brief was written by AAI Vice President Kathleen Bradish and AAI President Randy Stutz, with assistance from AAI General Counsel Mark Hegedus and AAI Senior Counsel David O. Fisher.
Read the full brief: AAI Amicus Brief in United States v. Google LLC
