DOJ seeks structural remedies including AdX divestiture while Google proposes behavioral fixes as closing arguments approach November 17 in antitrust trial.

DOJ and Google file final ad tech antitrust remedies proposals in Virginia court case.

On November 3, 2025, both the U.S. Department of Justice and Google filed their final post-trial briefs and proposed remedies in the Eastern District of Virginia antitrust case, setting up a critical showdown over how to address the company’s illegal monopolization of digital advertising markets. The competing visions outlined in the 44-page DOJ brief and 43-page Google filing present fundamentally different approaches to restoring competition, with closing arguments scheduled for November 17.

According to the DOJ’s filing, behavioral remedies alone cannot adequately address the “extraordinary harm Google inflicted on the relevant markets.” The Justice Department, along with attorneys general from multiple states, is pursuing sweeping structural remedies including complete divestiture of Google’s AdX ad exchange, open-sourcing of DoubleClick for Publishers’ (DFP) final auction logic, and contingent divestiture of DFP’s remaining components if competition is not restored.

Google counters that its proposed behavioral remedies would “fulfill the Court’s mandate to redress the violations and restore competition” without the disruption of breaking up integrated products. The company argues that divesting AdX would be “unprecedented,” “radical,” and “extreme” given that courts have historically reserved such measures for unlawful mergers rather than monopolization through business conduct.

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DOJ’s comprehensive remedy framework: structural changes to restore competition

The Department of Justice’s post-trial brief lays out a comprehensive remedial framework designed to address what prosecutors characterize as “extraordinary harm” inflicted on digital advertising markets through Google’s decade-long monopolization campaign. According to the November 3 filing, the government’s proposal centers on three interconnected structural remedies complemented by behavioral restrictions and robust monitoring provisions.

The Justice Department’s legal position rests on the principle that only structural changes can satisfy the four mandatory objectives of antitrust remedies established by Supreme Court precedent: unfettering markets from anticompetitive conduct, terminating illegal monopolies, denying defendants the fruits of violations, and ensuring no practices likely to result in future monopolization.

The centerpiece of the DOJ’s proposal requires Google to divest its entire AdX advertising exchange within 12 months of the court’s final judgment. According to the government brief, this divestiture would encompass all AdX functionality, intellectual property, customer relationships, and technical infrastructure necessary to operate the exchange independently.

The government argues that AdX divestiture would eliminate Google’s unilateral incentive to artificially handicap rival exchanges by ending the company’s economic motivation to maintain exclusive or preferential access to AdWords demand. According to testimony from Andrew Casale, CEO of Index Exchange, removing this incentive would create “fair competition” where customers choose ad exchanges “purely on their merits” rather than based on artificial advantages Google creates for its own products.

The divestiture would require Google to identify a suitable buyer capable of maintaining AdX’s functionality and serving its global customer base. According to the DOJ brief, potential acquirers include existing ad tech companies seeking to consolidate market position, technology companies seeking entry into advertising markets, or private equity firms with operational expertise in advertising technology.

Google’s internal documents from Project Sunday in 2020 and Project Monday in 2021 contemplated complete AdX shutdown and divestiture scenarios remarkably similar to what the DOJ now proposes. According to testimony from Tim Craycroft, Google’s VP in charge of display products, these analyses examined transferring the AdX business to another company, providing reference source code, and implementing a transitional period during which the buyer would rebuild AdX on their own infrastructure.

The government brief notes that Google’s contemporaneous analyses anticipated a buyer would “rebuild AdX on their own stack” with the existing version continuing to run in Google’s environment while the acquirer replaced dependencies. These internal documents undermined Google’s trial testimony that divestiture would be technically infeasible or would necessarily degrade product quality.

Phased approach to DFP with open-source auction logic

The DOJ proposes a phased approach to addressing Google’s monopoly in the publisher ad server market, beginning with mandatory open-sourcing of DFP’s final auction logic. According to the government brief, this component represents the “pivotal algorithms that dictate which ads are shown on more than 90% of websites worldwide.”

Under the proposal, Google would be required to make DFP’s final auction logic—including algorithms that select between direct deals and indirect bids, implement yield optimization, and execute multi-slot auctions—available under an open-source license within 12 months. The code would be administered by a neutral industry body, with Prebid.org identified as a capable administrator.

According to testimony from Michael Racic, Prebid’s President, the industry group has experience seamlessly rolling out new versions of open-source software and stands ready to administer the auction code. Publishers would be able to instruct their ad server to implement the open-source logic, with new versions automatically incorporated as they become available.

The government brief explains that open-sourcing the auction logic would reduce barriers to entry in the publisher ad server market by eliminating the need for new entrants to develop sophisticated auction algorithms from scratch. According to DOJ economist Professor Robin Lee, this would save potential competitors years of development time and millions of dollars in research and development costs.

Open-sourcing would also provide transparency into how DFP selects winning ads, addressing publisher concerns about Google using proprietary algorithms to favor its own ad exchange. According to testimony from multiple publishers including Daily Mail’s Matthew Wheatland, lack of transparency into DFP’s final auction logic prevents publishers from verifying whether Google treats all ad exchanges fairly.

The proposal includes specific technical requirements for the open-source implementation. Google would be required to provide comprehensive documentation explaining how the auction logic functions, data necessary for the logic to operate effectively, and support for publishers and service providers implementing the code. According to the DOJ brief, Google would remain prohibited from using proprietary data or features unavailable to competitors when implementing the open-source auction within its own DFP product.

Contingent divestiture of DFP remainder

The DOJ’s proposal includes a contingent divestiture mechanism for DFP’s remaining components if open-sourcing the auction logic proves insufficient to restore competition. According to the government brief, this “DFP Remainder” would encompass all publisher ad server functionality except the final auction logic, including ad trafficking tools, yield management features, reporting systems, and integration capabilities.

The contingent divestiture would be triggered three years after the initial remedies take effect if plaintiffs demonstrate that the publisher ad server market has not experienced substantial increased competition. According to the proposal, plaintiffs would need to show by a preponderance of evidence that barriers to entry remain prohibitively high, customer switching has not occurred at meaningful levels, or Google has maintained its monopoly position through other means.

If triggered, the divestiture would require Google to sell DFP Remainder to one or more buyers within 18 months. The government brief notes that multiple acquirers could be appropriate to prevent excessive market concentration, particularly given DFP’s current 91% market share.

According to Google’s internal Project Monday documents, the company previously analyzed transforming DFP into a standalone Google Cloud Platform product, demonstrating technical feasibility of separating the publisher ad server from Google’s integrated advertising infrastructure. The government brief cites these analyses as evidence that contingent divestiture could be implemented if necessary.

Comprehensive behavioral restrictions

Beyond structural remedies, the DOJ proposes extensive behavioral restrictions designed to prevent Google from recreating anticompetitive advantages through its remaining advertising products. These restrictions would apply for ten years, far longer than the three-year monitoring period Google proposed.

The behavioral remedies address both buy-side and sell-side practices. On the buy side, the proposal would prohibit Google from tying AdWords demand to any particular publisher ad server or ad exchange, require AdWords to bid into all qualifying ad exchanges on equal terms, and prevent Google from using differential pricing or data advantages to favor its own products.

According to the government brief, these buy-side restrictions address the “motive and means to recreate the ties” that violated antitrust law. Without structural separation, Google would retain economic incentive to use AdWords’ unique demand as leverage to disadvantage competitors in adjacent markets.

On the sell side, the proposal would require Google to provide rival publisher ad servers with equal access to AdX bids, prohibit reinstatement of First Look or Last Look features that gave AdX preferential treatment, and prevent implementation of pricing rules that restrict publisher control over their inventory.

The proposal includes specific technical requirements for these behavioral restrictions. Google would be required to maintain equivalent latency, data signals, bid volumes, and revenue shares across all integration pathways, whether publishers use DFP, rival ad servers, or Prebid. According to testimony from industry witnesses, subtle variations in any of these parameters could recreate competitive disadvantages the remedies aim to eliminate.

Data sharing and interoperability requirements

The DOJ proposes mandatory data sharing provisions designed to enable competitors to achieve scale and functionality comparable to what they would have attained absent Google’s illegal conduct. According to the government brief, Google’s monopolization deprived rivals of access to data necessary to optimize their products and compete effectively.

Under the proposal, Google would be required to provide publishers with comprehensive historical data from DFP, including information about ad impressions, bids, auction outcomes, and revenue. Publishers switching to rival ad servers would be able to transfer this data, eliminating informational barriers to switching.

The proposal also requires Google to provide rival ad servers with ongoing access to AdX bid data for impressions served through their products. According to testimony from James Avery of Kevel, access to this bid-level data would enable rival ad servers to offer analytics and optimization features comparable to DFP.

For ad exchanges, the proposal would require AdX to provide equivalent information to all buying tools about bid opportunities, preventing Google from using information asymmetries to advantage its own demand-side platforms. According to the government brief, these information-sharing requirements would “level the playing field” that Google tilted through years of anticompetitive conduct.

Monitoring and enforcement framework

Recognizing the technical complexity of monitoring compliance in sophisticated technology markets, the DOJ proposes a robust oversight structure centered on an independent monitoring trustee with unprecedented access and authority.

The monitoring trustee would serve for six years, double the three-year period Google proposed, with authority to access Google’s source code, technical documentation, business records, and employees. According to the government brief, the trustee would have power to investigate potential violations, require modifications to Google’s products, and report non-compliance to the court.

The proposal includes specific requirements for trustee qualifications, independence, and resources. The trustee would need technical expertise in advertising technology, software engineering, and auction design, along with authority to hire expert consultants as necessary. Google would bear all costs of the monitoring trustee’s operations.

Beyond the monitoring trustee, the proposal establishes a technical compliance framework requiring Google to document all material changes to its advertising products, maintain detailed logs of auction mechanics and business practices, and provide regular reports demonstrating compliance with remedial provisions.

The proposal also creates an escrow fund to facilitate publisher switching. Google would be required to contribute funds that publishers could use to offset costs of migrating from DFP to rival ad servers, including technical integration expenses, testing and optimization costs, and short-term revenue risks. According to testimony from Prebid’s Michael Racic and Magnit’s Ben Créput, such financial support would materially reduce switching costs that currently deter publishers from adopting alternatives.

Anti-circumvention provisions

The DOJ proposal includes detailed anti-circumvention provisions designed to prevent Google from using new methods to replicate the anticompetitive effects of conduct the court found illegal. According to the government brief, these provisions are necessary because “there are innumerable ways Google could modify its technology to recreate anticompetitive effects.”

The anti-circumvention provisions prohibit specific categories of conduct including manipulating latency to favor Google products, altering data signals to provide advantages to Google tools, modifying decision algorithms in ways that discriminate against competitors, implementing pricing schemes that make non-Google pathways more expensive, creating new exclusive or preferential relationships, and restricting transaction types available through rival systems.

The proposal includes a catch-all provision prohibiting any conduct that has the purpose or effect of recreating the competitive harm caused by Google’s illegal tying, First Look, Last Look, or Unified Pricing Rules. According to the government brief, this catch-all is necessary because “even the most comprehensive injunction can hardly be detailed enough to cover in advance all the many fashions in which anticompetitive conduct might manifest.”

Legal justification for structural relief

The DOJ’s legal argument for structural remedies rests on established Supreme Court precedent approving divestiture as the preferred remedy for monopolization. According to the government brief, structural remedies are particularly appropriate where, as here, the defendant acquired rather than merely maintained monopoly power through anticompetitive conduct.

The brief distinguishes the case from Microsoft and Google Search, where courts found companies only illegally maintained existing monopolies. Here, Judge Brinkema found Google “willfully engaged in a series of anticompetitive acts to acquire and maintain monopoly power” in markets where it previously lacked dominance.

According to the DOJ, this distinction is legally significant because the Supreme Court has held that remedies must “deny to the defendant the fruits of its statutory violation.” When a company acquires monopoly power through illegal conduct, allowing it to retain that power leaves the fruits of violation in place even if future conduct is regulated.

The brief also argues that structural remedies are justified by the technical complexity and opacity of Google’s products, which make behavioral remedies difficult to monitor and enforce. According to testimony from industry participants, Google can manipulate algorithmic decision-making in ways too subtle to detect, making ongoing behavioral oversight impractical.

Finally, the government argues that structural remedies are necessary because behavioral remedies alone would require the court to become a “central planner” of competition in advertising technology markets. According to the brief, this would exceed “the practical limits of judicial administration” that the Supreme Court has warned courts to respect.

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Industry consensus supports structural intervention

The remedies trial, which ran from September 22 through early October 2025, featured testimony from 19 fact witnesses and seven experts. According to the DOJ brief, nearly every third-party industry participant who testified explained that competition cannot be restored if Google retains control over DFP and AdX.

Publishers, ad exchanges, advertisers, and buy-side platforms testified that only structural changes would provide sufficient assurance to encourage the market entry, investment, and customer switching necessary to rebuild competition in markets where Google holds over 90% market share in publisher ad servers and 63-71% market share in ad exchanges.

Matthew Wheatland, Chief Digital Officer at Daily Mail, testified his business “needs to be sure” remedies will have “lasting effects” and would not have that assurance without structural relief. The lack of confidence would create “friction” making it “harder for us to switch publisher ad servers,” which would drag on competitive ad servers by reducing new customers and revenue needed for investment.

Andrew Casale, CEO of Index Exchange, explained that without structural changes, “a very creative mind can develop another preferencing feature to implement into DFP tomorrow.” James Avery of Kevel testified there would be no “guarantee that customers are going to get the same demand on Kevel that they were getting on DFP,” leaving potential customers “worried” about switching.

Competing proposals reveal stark differences

The Justice Department’s remedies proposal centers on three structural components. First, complete divestiture of AdX to eliminate Google’s incentive to artificially handicap rival ad exchanges. Second, open-sourcing DFP’s final auction logic to reduce barriers to entry in the publisher ad server market and provide transparency into algorithms that dictate which ads appear on over 90% of websites worldwide. Third, contingent divestiture of DFP’s remaining components if these measures prove insufficient within three years.

According to the DOJ filing, structural remedies are necessary because “the innumerable ways Google could modify its technology to recreate the anticompetitive effects of its illegal campaign” make comprehensive behavioral remedies impractical. The government identified numerous potential methods for re-monopolization including manipulating latency, altering data signals, modifying decision algorithms, implementing differential pricing, creating new exclusive relationships, restricting transaction types, and limiting bid volume.

Google proposes behavioral remedies including making real-time AdX bids available to rival publisher ad servers, removing Unified Pricing Rules, committing not to rebuild First Look or Last Look features, and appointing a monitoring trustee for six years. The company updated its proposal during trial to formalize commitments ensuring these integrations would effectively break the AdX-DFP tie.

Tim Craycroft, Google’s Vice President in charge of display products, testified the company would provide rival ad servers and Prebid access to AdX real-time bids for all indirect demand, would not bid differently through various pathways, would not vary AdX revenue share based on publisher ad server choice, and would provide the monitor with necessary verification information.

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Feasibility battle centers on technical complexity

A central dispute involves whether proposed structural remedies are technically feasible. The DOJ presented evidence including Google’s own internal analyses showing feasibility, while Google emphasized complexity and potential degradation of product quality.

According to the DOJ brief, Google’s internal engineering documents from Projects Sunday, Monday, and 2023-2024 technical evaluations confirm that proposed migrations are technically feasible and can be achieved in reasonable timeframes. These contemporaneous analyses directly addressed technical implementation questions that dominated trial testimony.

Professor Marc Weissman, the DOJ’s technical expert, testified that AdX can be divested by copying and migrating technical assets to a new environment and replacing general-purpose systems upon which it relies. Dr. Katja Bjedov estimated AdX migration could be completed in 18 months and DFP Remainder in 24 months using standard migration processes.

Google witnesses attempted to distance themselves from the company’s own feasibility conclusions. Craycroft, Engineering Director Aaron Levitte, and Principal Engineer Glenn Berntson testified that internal documents analyzing divestiture represented “brainstorming” rather than definitive assessments, despite being communicated to senior business leaders before the liability trial.

Professor Jason Nieh, Google’s technical expert, warned that divestiture would create unprecedented complexity requiring replacement of dependencies representing 27 years of Google investment. However, Nieh did not claim divestiture was impossible, only that there was no certainty about timeline and quality outcomes.

Open-sourcing proposal draws on antitrust precedent

The DOJ’s proposal to open-source DFP’s final auction logic builds on antitrust remedies that broadened access to important intellectual property in past cases. The 1956 AT&T antitrust decree included compulsory, royalty-free patent licensing that led to creation of the technology industry and Silicon Valley startups.

According to research cited in the DOJ brief, the AT&T remedy encouraged third-party use of transistor technology, leading to rapid growth of companies like Shockley Semiconductor, Fairchild, Texas Instruments, and Intel. Similarly, the breakup of the AT&T monopoly in the 1980s reduced long-distance phone rates, increased industry productivity, spurred fiber optic deployment, and reduced equipment prices.

Michael Racic, President of Prebid.org, testified the industry group is ready to administer open-sourced auction code and has experience seamlessly rolling out new versions of open-source software. Google’s internal documents show the company estimated open-sourcing the final auction logic would take no more than four years.

The open-source auction would allow any publisher ad server—including DFP itself—to run the final auction logic on behalf of publisher customers. Publishers could instruct their ad server to implement the open-source auction code, with new versions automatically incorporated into DFP as the default.

Market dynamics complicate remedy considerations

Google warned that open-web display advertising already faces “rapid decline,” with only 11% of display impressions purchased by AdWords advertisers going to open-web display in January 2025, down from over 40% in January 2019. The company argues divestiture would create perverse incentives accelerating this decline.

According to Google’s brief, forcing divestiture for open-web display while allowing continued operation of advertising tools for other formats would “incentivize Google to shift the resources it invests in serving open-web publishers to serving publishers who prioritize other formats, like app and CTV.”

The DOJ counters that Google’s illegal conduct itself acts as a drag on open-web display, discouraging investment and innovation by ad tech providers and making it less attractive for advertisers. Greater competition would help reverse negative trends by increasing incentives to invest and innovate, thereby offering advertisers better return on investment.

Multiple witnesses testified that advances in machine learning and generative AI have not reduced Google’s chokehold on relevant ad tech markets. If anything, because Google is “an AI-first company” that has been expanding investments in AI, these technologies are more likely to entrench rather than challenge Google’s ad tech dominance.

Legal standards favor government position

The DOJ argues the case presents facts demanding structural relief under longstanding Supreme Court precedent. The Court found Google acquired—not merely maintained—monopolies in two interconnected markets through a decade-long campaign of ever-mutating unlawful conduct. In that context, courts have routinely approved divestiture as the “most important” and “most effective” antitrust remedy.

According to the government brief, “structural remedies are justified where a firm acquired monopoly power through anticompetitive conduct, as the Court found here.” The DOJ distinguishes the case from Microsoft and Google Search, where courts found companies only illegally maintained rather than acquired monopolies.

Google argues no court has awarded divestiture where the gravamen of violation was unlawful tying among products rather than unlawful merger or conspiracy. The company claims divestiture should be reserved for cases involving “intercorporate combination and control” rather than monopolization through business practices.

The Justice Department responds that multiple Supreme Court cases approved divestiture to remedy tying-related conduct, including Paramount Pictures, Crescent Amusement, and Schine Chain Theatres. In each case, courts ordered defendants to divest ownership interests or business assets that were instruments of tying arrangements.

Private litigation looms as pressure mounts

Google faces cascading private lawsuits following the liability ruling. On October 27, 2025, the Southern District of New York granted partial summary judgment to multiple private plaintiffs, ruling that Judge Brinkema’s findings would have binding effect in damages litigation.

Publishers including Associated Newspapers, Mail Media, and Gannett can now proceed directly to proving damages based on established findings that Google maintained over 90% market share in publisher ad servers from 2018 to 2022. Magnite, OpenX, PubMatic, and Raptive have filed follow-on antitrust lawsuits seeking damages.

Law firms have launched aggressive recruitment seeking advertisers who may have been financially harmed, promising potential refunds of up to 30% on advertising expenditures since 2016. The legal outreach targets brands that spent on Google advertising, claiming the company overcharged advertisers through auction manipulation.

Advertisers have one lone supporter in WikiHow CEO Elizabeth Douglas, who testified for Google that removing AdX as a competitor “scares” her because “there’s just no SSP that I trust as much as Google.” However, Douglas conceded signing a content licensing agreement with Google representing 10-15% of WikiHow’s yearly revenues, raising questions about bias.

Closing arguments will crystalize positions

Judge Leonie Brinkema will hear closing arguments on November 17, 2025, in Alexandria, Virginia. The arguments will provide both sides final opportunity to synthesize three weeks of testimony and hundreds of exhibits into cohesive narratives about how to restore competition.

The Justice Department will emphasize that only structural remedies can satisfy four mandatory objectives of antitrust decrees: unfettering markets from anticompetitive conduct, terminating illegal monopolies, denying defendants the fruits of violations, and ensuring no practices likely to result in future monopolization.

Google will argue its behavioral proposals would restore competition without the risks and disruption of forced divestitures. The company will emphasize that no divestiture has ever been ordered to remedy product tying, that separating integrated technology assets creates unprecedented complexity, and that publishers and advertisers could suffer during transitions.

The stakes extend beyond this case. Google simultaneously faces remedies proceedings in the search monopolization case, where the Justice Department seeks Chrome browser divestiture. Combined, the cases target both search advertising that generates 57% of Alphabet’s revenue and underlying ad technology infrastructure facilitating digital advertising transactions across the internet.

Marketing professionals must prepare for potential fundamental changes to digital advertising infrastructure. The industry impact extends to emerging technologies, as these cases affect not just current market dynamics but future technological development in search and advertising.

Timeline

• 2008: Google acquires DoubleClick for $3.1 billion
• 2011: Google acquires Admeld yield management platform
• 2017: Google implements Project Poirot to reduce DV360 bids on rival exchanges
• 2019: Google implements Unified Pricing Rules restricting publishers’ pricing flexibility
• January 24, 2023: DOJ files antitrust lawsuit against Google targeting ad tech practices
• September 2024: Three-week liability trial concludes with extensive technical testimony
• April 17, 2025: Judge Brinkema rules Google monopolized digital advertising markets
• May 5, 2025: Both parties submit competing remedy proposals
• August 15, 2025: Court documents reveal extensive witness lists and exhibits
• September 22-October 6, 2025: Remedies trial presents testimony from industry participants and technical experts
• September 25, 2025: Google VP testifies about internal feasibility studies for proposed remedies
• October 27, 2025: SDNY grants summary judgment to private plaintiffs using Virginia findings
• November 3, 2025: DOJ and Google file final post-trial briefs and proposed remedies
• November 17, 2025: Closing arguments scheduled in Alexandria, Virginia

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Summary

Who: The U.S. Department of Justice, 17 state attorneys general, and Google LLC in the Eastern District of Virginia antitrust case, with testimony from publishers including Daily Mail and WikiHow, ad exchanges Index Exchange and PubMatic, advertisers, and technical experts.

What: Final post-trial briefs presenting competing remedies proposals—DOJ seeking structural relief including AdX divestiture and open-sourcing DFP auction logic versus Google proposing behavioral remedies including real-time bid sharing and removing discriminatory practices.

When: Filings submitted November 3, 2025, following remedies trial from September 22 through early October 2025, with closing arguments scheduled November 17, 2025, after April 17, 2025 liability ruling.

Where: U.S. District Court for the Eastern District of Virginia in Alexandria, where Judge Leonie Brinkema found Google violated Sherman Act by monopolizing publisher ad server market (over 90% share) and ad exchange market (63-71% share).

Why: The remedies will determine whether Google must divest major ad tech assets or can address antitrust violations through operational changes, with implications for $700 billion digital advertising ecosystem, thousands of publishers depending on open-web display revenue, and future of online advertising competition globally.