A legal reckoning for the digital ad market
By willowt // 2025-09-23
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  • A federal judge has ruled that Google illegally monopolized key parts of the digital advertising market.
  • A "remedy" trial is now underway to determine how to restore competition, with the Justice Department pushing for a breakup of Google's ad technology.
  • Google argues its proposed technical fixes are sufficient and that a forced divestiture would harm the internet ecosystem.
  • The case follows a separate, less severe antitrust ruling against Google's search monopoly, which may influence the current proceedings.
  • The outcome could fundamentally reshape the $305 billion digital advertising market that funds much of the open web.
In a federal courtroom in Alexandria, Virginia, a high-stakes legal battle is unfolding that threatens the core of Google's vast digital advertising empire. The proceeding, which began Monday, September 22, represents the latest and one of the most significant antitrust challenges to Big Tech's dominance. Presided over by U.S. District Judge Leonie Brinkema, this "remedy" phase follows her landmark April ruling that declared parts of Google’s ad technology an illegal monopoly. The Justice Department, building on a case initially filed in 2023, is now seeking a dramatic restructuring of Google’s business, arguing it is the only way to dismantle a system that has stifled competition for years. The outcome will not only determine the future of a company that has become synonymous with online advertising but could also redefine the competitive landscape of the entire internet.

The core of the monopoly allegations

The case centers on the complex, interconnected systems that Google has built over nearly two decades to facilitate the buying and selling of online display ads. Judge Brinkema’s earlier ruling found that Google unlawfully monopolized the markets for publisher ad servers, through its DoubleClick for Publishers (DFP) product, and ad exchanges, via its AdX platform. The court determined that Google illegally tied these two services together, creating a self-reinforcing cycle that discouraged publishers from using competing technologies. This ecosystem, the Justice Department argues, allowed Google to act as both the operator of the dominant auction house (AdX) and a powerful participant with privileged access, ultimately inflating costs for advertisers and reducing revenue for publishers. This business accounts for the majority of the $305 billion in revenue generated by Google's services division, forming the financial backbone of its parent company, Alphabet Inc.

Divergent visions for a remedy

The central conflict in the current trial is the stark disagreement between the Justice Department and Google over how to fix the market. The government’s proposal is structural and severe: it wants the court to force Google to divest its key ad exchange, AdX. The DOJ contends this is the most direct way to break the feedback loop that entrenches Google’s power. In parallel, it seeks to have Google’s auction logic open-sourced to ensure transparency. A breakup, the DOJ asserts, is the quickest path to fostering genuine competition. Google, unsurprisingly, rejects this approach. The company’s lawyers have warned that a divestiture would “invite disruption and damage” to consumers and the internet's ecosystem. Instead, Google has proposed a series of behavioral remedies, arguing they are sufficient to address the court’s concerns. These proposals include:
  • Deeper interoperability to allow rival ad servers better access to Google’s ad demand.
  • The elimination of certain auction rules that disadvantaged competitors.
  • A commitment not to use specific technical advantages for open web ads.
Lee-Anne Mulholland, Google's vice president of regulatory affairs, stated in a prepared comment, “Breaking apart integrated tools would make it harder for publishers to monetize their content and more expensive for advertisers to reach new customers, disproportionately hurting the small businesses who choose to use Google’s tools to grow.”

The shadow of the search case

This advertising technology trial closely mirrors a separate antitrust case targeting Google’s search monopoly, which was recently decided by U.S. District Judge Amit Mehta. In that case, the Justice Department also pushed for a breakup, specifically the divestiture of Google’s Chrome browser. However, Judge Mehta ultimately opted for a less dramatic set of behavioral remedies, a ruling widely perceived as a victory for Google. Judge Brinkema has explicitly asked both sides in the ad tech case to address Judge Mehta’s decision, indicating it may influence her final ruling. Google’s legal team is already leveraging the precedent, arguing that the court should similarly avoid “radical” proposals, especially in a market they claim is being rapidly reshaped by artificial intelligence and competition from rivals like Meta Platforms.

A shifting market awaits a court's decision

A critical question hanging over the trial is whether a court-ordered remedy can keep pace with the rapidly evolving digital landscape. Even as the legal arguments proceed, the open web that Google’s ad tech once dominated is already splintering into new arenas like retail media networks and AI-native interfaces. Google itself has been quietly losing market share in some ad tech segments. Some industry observers suggest that whatever remedy is imposed may serve as a temporary lift for competitors rather than a full-scale reckoning, providing a float for an ad-funded internet still searching for its next sustainable model. The court’s timeline suggests a final ruling from Judge Brinkema is unlikely before 2026, and an appeal from Google is a near certainty regardless of the outcome. This ensures that the legal and competitive future of digital advertising will remain uncertain for years to come.

An antitrust crossroads

The trial in Alexandria represents a pivotal moment in the ongoing reassessment of antitrust enforcement in the digital age. The DOJ’s aggressive pursuit of a structural breakup signals a significant shift in thinking about how to address the power of dominant online platforms. For businesses and publishers who have long felt constrained by Google’s vast user base and market position, the case offers a potential path to a more competitive environment. However, as the contrasting outcome in the search case demonstrates, there is no guaranteed result. The final decision will test the limits of existing antitrust laws and determine whether the government can successfully compel a tech giant to dismantle the very architecture of its success, with far-reaching implications for how information is monetized and accessed online for a generation. Sources for this article include: TheNationalPulse.com Independent.co.uk Digiday.com
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