The U.S. Department of Justice and Google have concluded a pivotal two-week hearing that will determine the future structure of the online advertising ecosystem. This remedies phase follows a landmark ruling by Judge Leonie M. Brinkema on April 17, 2025, which found Google had illegally monopolized key markets within the ad tech stack2. The DOJ is now seeking a structural breakup of Google’s advertising business, a move the company has labeled as “radical” and “extreme”8. The outcome of this case is poised to have major effects on online advertising, potentially reshaping the revenue models that fund much of the open web.
Technical Breakdown of Google’s Ad Tech Monopoly
The court found Google monopolized two specific markets in the open-web display advertising space: the publisher ad server market, dominated by Google’s DFP (now Google Ad Manager), and the ad exchange market, controlled by Google’s AdX2. The technical violations were multifaceted and systemic. Google engaged in illegal tying by forcing publishers using its ad server to also use its AdX exchange4. The company also implemented auction manipulation through “First Look/Last Look” advantages within its ad exchange, providing its own systems with preferential treatment. Internal evidence presented at trial revealed that Google was aware its Ad Exchange was not worth its 20% fee but refused to lower it, effectively charging monopoly rents9. This conduct directly sabotaged competing technology and created an environment where Google could control both the supply and demand sides of the advertising market while operating the central exchange.
The Proposed Remedies: Structural Breakup vs. Behavioral Changes
The DOJ’s Proposed Final Judgment calls for a structural solution to what it characterizes as an inherently conflicted business model2. The government is specifically seeking the divestiture of Google’s AdX exchange and potentially parts of its DFP publisher ad server4. In its opening statement, the DOJ framed Google as a “recidivist monopolist” that cannot be trusted with behavioral fixes alone7. Google has countered with a proposal for limited behavioral changes that would eliminate its “Unified Pricing” rules and “first/last look” advantages, but significantly, only for open-web display ads8. The company seeks to exclude key, growing ad formats like Connected TV (CTV) and video from these restrictions, arguing this maintains its ability to compete against other walled gardens like Facebook and Amazon.
Broader Implications for the Digital Ecosystem
The financial impact of Google’s ad tech practices extends throughout the digital publishing industry. The domination of open-web display advertising has been directly linked to the financial crisis facing web publishers and journalism9. As Google intermediates the relationship between publishers and advertisers, it extracts revenue that traditionally supported media organizations, leading to more paywalls and media closures. The case highlights the critical distinction between “open-web” advertising on independent websites and ads within closed “walled gardens” like Facebook, TikTok, or Amazon9. A central question in the remedies phase is whether Google can evade a complete remedy for illegally monopolizing a market by arguing that competition has expanded beyond the very market it helped diminish through its anticompetitive conduct.
International Alignment and Legal Precedents
The legal proceedings in the United States are occurring alongside significant international regulatory action. The European Union recently found Google liable for the same ad tech monopolization practices and fined the company $3.5 billion10. Notably, the EU Commission stated that “only the divestment by Google of part of its services would address the situation of inherent conflicts of interest,” signaling global regulatory consensus on the need for structural remedies10. Google’s legal arguments heavily rely on the recent Search case ruling by Judge Mehta, which featured less aggressive remedies, and the quarter-century old U.S. v. Microsoft case10. The DOJ’s proposal, however, is backed by citations to older but controlling Supreme Court decisions that support structural intervention in cases of entrenched monopoly power.
The remedies hearing represents a critical juncture for antitrust enforcement in digital markets. Judge Brinkema’s final ruling will determine whether behavioral modifications are sufficient to restore competition or whether structural separation is necessary to address the fundamental conflicts in Google’s ad tech stack. The decision will establish important precedents for regulating dominant platforms and could significantly impact the technical architecture of digital advertising systems. With parallel cases concluding against Google’s search monopoly and international regulators taking aligned action, the outcome of this hearing may signal a new era of antitrust enforcement for technology platforms.
