The Google Monopolization Decisions: A Roadmap for Private Antitrust Plaintiffs

August 31, 2026

Author: Luis Blanquez

In recent years, Google has faced antitrust scrutiny from the government and private civil litigants for its practices in online search and advertising. Two actions brought by the government—United States v. Google, 20-cv-3010 (APM) (D.D.C.) and United States v. Google, 23-cv-0108 (LMB/JFA) (E.D. Va.)—culminated in landmark findings that Google is a monopolist. 

A growing number of advertisers, publishers, and other businesses have filed and are litigating actions challenging substantially similar misconduct by Google. Advertisers bound to arbitrate with Google have initiated individual and mass arbitrations seeking recovery for Google’s alleged overcharges. Publishers and advertisers not bound to arbitrate have pursued class actions, some of which are consolidated in the multidistrict proceeding in the Southern District of New York before Judge P. Kevin Castel in In re Google Digital Advertising Antitrust Litigation, MDL No. 3010 (S.D.N.Y.). Under Section 4 of the Clayton Act, 15 U.S.C. § 15, these private plaintiffs may recover treble damages and attorneys’ fees, subjecting Google to even greater exposure.

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The government’s recent victories in the District of Columbia and Eastern District of Virginia equip these private litigants with a powerful potential advantage—collateral estoppel (i.e., issue preclusion). Critically, Section 5(a) of the Clayton Act, 15 U.S.C. § 16(a), provides that a final judgment against an antitrust defendant in a government case serves as prima facie evidence of the violation in later private actions. Thus, private litigants may leverage the findings in Judge Mehta’s and Judge Brinkema’s decisions to establish key elements of their claims. 

Indeed, in In re Google Digital Advertising Antitrust Litigation, Judge Castel recently found that numerous plaintiff groups may invoke offensive non-mutual collateral estoppel, thus precluding Google from relitigating Judge Brinkema’s findings on the relevant product market, Google’s monopoly power, and various aspects of Google’s exclusionary conduct. In re Google Digital Advert. Antitrust Litig., No. 21-CV-3446 (PKC), 2025 WL 3012840, at *1, 17-18 (S.D.N.Y. Oct. 27, 2025). 

Google faced similar collateral estoppel consequences in Yelp Inc. v. Google LLC, No. 24-cv-06101-SVK (N.D. Cal.). In that action, Yelp alleges that, among other things, Google monopolized the market for local search services, including by leveraging its power in the market for general search services. Yelp Inc. v. Google LLC, 2026 WL 1883619, at *1 (N.D. Cal. June 30, 2026). On June 30, 2026, after Yelp’s motion, Magistrate Judge Susan van Keulen issued an order precluding Google from relitigating specified findings by Judge Mehta about the general search services market definition and Google’s monopoly power in that market. Id. at *14. 

Bottom line: as the number of private actions against Google stacks up, the issue preclusion doctrine will serve as a powerful tool for private plaintiffs to recover from Google for its wrongdoing.

Below is more detail about the relevant government cases that form the basis of these issue preclusion (collateral estoppel) arguments.

United States v. Google, 20-cv-3010 (APM) (D.D.C.)

On October 20, 2020, the United States Department of Justice and several state attorneys general (“United States Plaintiffs”) filed suit against Google in the District of Columbia. Judge Amit Mehta presides over the action. In it, the government asserted that Google unlawfully maintained its monopoly in three product markets by entering into exclusive agreements to secure default distribution on nearly all desktop and mobile devices in the United States. This suit was later consolidated with a follow-on suit under the Clayton Act (15 U.S.C. § 26), Colorado v. Google, 20-cv-3715 (APM) (D.D.C.), brought by 38 states suing in parens patriae capacity. While the follow-on suit overlapped with the first action, that second action advanced additional challenges. 

The parties engaged in nearly two years of discovery, which concluded in March 2023. In August 2023, Judge Mehta granted in part and denied in part Google’s motions for summary judgment, entering judgment for Google on (i) specified aspects of the United States Plaintiffs’ claims, including regarding Android, and (ii) the Colorado action’s theory that Google’s targeting of specialized vertical providers caused anticompetitive effects in the proposed markets. Judge Mehta permitted the remaining claims to proceed to trial. 

Judge Mehta commenced a bench trial on September 12, 2023, and the evidentiary phase (with testimony from dozens of witnesses) concluded on November 16, 2023. In an August 5, 2024 decision, Judge Mehta concluded that Google violated Section 2 of the Sherman Act. Judge Mehta found that Google is a monopolist in the markets for general search services, United States v. Google LLC, 747 F. Supp. 3d 1, 32, 124 (D.D.C. 2024), and general search text advertisements, id. at 136-39. He further found that Google acted to maintain its monopoly in these markets by entering exclusive distribution agreements with browser developers (e.g., Apple), original equipment manufacturers (e.g., Samsung), and carriers (e.g., T-Mobile). Id. at 32, 146-52. Under those agreements, Google’s partners “agree to install Google as the default search engine delivered to the user right out of the box at key search access points” and “not to preload any other general search engine on the device.” Id. at 32. In return, Google would pay “huge sums” to secure its preloaded default. Id.

According to Judge Mehta, Google’s exclusive agreements caused anticompetitive effects in the market for general search services, including substantially foreclosing rivals from entering that market, depriving rivals of scale, and reducing incentives to invest and innovate in search. Id. at 152-71. These agreements also generated anticompetitive effects in the market for search text advertisements, again substantially foreclosing rivals from entering that market, enabling Google to degrade text advertisement quality, capping rivals’ advertising revenue, and permitting Google to charge supra-competitive prices for text advertisements. Id. at 177-81. As put by Judge Mehta, “[t]hese distribution deals have forced Google’s rivals to find other ways to reach users” and—perhaps most notably for potential future plaintiffs—Google’s conduct “allowed [it] to earn monopoly profits.” Id. at 32-33. 

On September 2, 2025, Judge Mehta issued his remedies decision. United States v. Google LLC, 803 F. Supp. 3d 18 (D.D.C. 2025). In it, Judge Mehta declined to impose the structural relief sought by the United States Plaintiffs, including forcing Google to divest Chrome and Android. See, e.g., id. at 37. 

Instead, Judge Mehta ordered numerous narrower remedies. Among other conditions, Judge Mehta prohibited Google from entering or maintaining exclusive agreements tying the distribution, licensing, or monetization of Google Search, Chrome, Google Assistant, or the Gemini app to the placement of its search services. Id. Critically, however, Judge Mehta declined to bar Google’s revenue share payments to distributors such as Apple outright, id., permitting Google to continue paying for default placement so long as the underlying arrangements remain nonexclusive. 

To address Google’s entrenched scale advantage, the court ordered Google to share certain search index and user interaction data with “qualified competitors,” id. at 37-38, and to offer search and search text advertising syndication on standard commercial terms, while declining to compel Google to share certain advertising data. Id. at 38. Judge Mehta further required Google to disclose material changes to its ad auction mechanics and also established a technical committee to assist in implementing and enforcing the judgment, which will be in effect for six years. Id. at 39.

Both Google and the United States Plaintiffs have appealed Judge Mehta’s decisions to the United States Court of Appeals for the District of Columbia Circuit. The appeal remains pending and, as of late August 2026, oral argument has not been scheduled.

United States v. Google, 23-cv-0108 (LMB/JFA) (E.D. Va.) 

On January 24, 2023, the United States Department of Justice and numerous states filed another suit against Google in the Eastern District of Virginia. Judge Leonie Brinkema presides over the action. In it, plaintiffs alleged that Google monopolized (or attempted to monopolize) the (i) publisher ad server for open-web display advertising market (which alerts sources of advertising demand about an impression for sale), (ii) ad exchange for open-web display advertising market (which connects publishers using publisher ad servers with advertisers using programmatic buying tools), and (iii) advertiser ad networks for open-web display advertising market (which connects publishers’ inventory with advertisers’ ads). United States v. Google LLC, 778 F. Supp. 3d 797, 810-11 (E.D. Va. 2025). Plaintiffs further alleged that Google unlawfully tied its products in those markets. Id. 

The parties engaged in one year of discovery, which concluded in March 2024. Judge Brinkema denied Google’s motion for summary judgment.

Following a three-week bench trial, Judge Brinkema found, in an April 17, 2025 decision, that Google possessed monopoly power in the (i) publisher ad server for open-web display advertising market, 778 F. Supp. 3d at 810, 850-52, and (ii) ad exchange for open-web display advertising market, id. at 810, 852-56. Judge Brinkema determined that Google willfully acquired and maintained such power through multiple measures, including (i) tying its publisher ad server to Google’s ad exchange, id. at 859-64, and (ii) a host of policies, practices, and technology changes to Google’s sell-side ad tech tools that were not in publisher customers’ best interests, id. at 864-66. Judge Brinkema rejected Google’s contentions that its anticompetitive conduct was justified by its procompetitive benefits. Id. at 868-72.

As of late August 2026, Judge Brinkema has not yet issued a remedies decision. Given that Judge Brinkema has not entered judgment, Google has not filed a notice of appeal (although one is expected).

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