Google Ad Tech Antitrust Remedies Ruling Explained: A Six-Year Monitor and No AdX Sale

Google ad tech antitrust remedies ruling explained: the short answer

The court found that behavioural remedies would be enough to restore competition in the two ad tech markets Google was found to have monopolised, so it did not order Google to sell anything. The order of 2 September states that the plaintiffs' proposals for the divestiture of AdX, the open-sourcing of DFP's final auction logic and the contingent divestiture of the "DFP Remainder" were rejected, while "most of the parties' proposed behavioral remedies, as modified by this Court" were accepted, according to the order as reported by PPC Land.

In her opinion, Judge Brinkema wrote that the remedies will be "sufficient to effectively pry open to competition the ad tech markets that were injured by Google's unlawful conduct", Reuters reported. The measures will run for six years, the duration Google had proposed, rather than the 15 years the government wanted, according to The Next Web.

Three points matter most for advisers:

• No structural relief. AdX and DoubleClick for Publishers (DFP), now sold together as Google Ad Manager, stay under Google's ownership.
• Interoperability as the cure. Google must integrate its tools with the open-source Prebid framework and with rival publisher ad servers, and stop its advertiser tools from favouring its own exchange.
• Supervision, not a single event. The remedy depends on a monitor and technical committee policing compliance for six years, which makes implementation, rather than the opinion, the real battleground.

What the court ordered Google to do

The court ordered a set of interoperability, data and non-discrimination obligations that attack the technical links between Google's buy-side tools, its exchange and its publisher ad server. The Department of Justice's press release of 16 September 2026 lists four headline categories: integrations with Prebid and competing publisher ad servers, data sharing, non-discriminatory bidding by AdWords (now Google Ads), and monitoring. Trade reporting of the unsealed opinion adds further detail.

Remedy	What Google must do	Who it helps
AdX to Prebid integration	Build integrations so AdX demand can compete inside Prebid header bidding	Publishers using Prebid; rival ad servers
DFP to Prebid integration	Connect DFP to Prebid so publishers can run open auctions from Google's ad server	Publishers; rival exchanges
AdX bids to rival ad servers	Submit real-time AdX bids to competing publisher ad servers on the same terms as DFP receives them	Rival publisher ad servers
Bid data	Share real-time bid data, wins and losses, with publishers	Publishers pricing their inventory
Data export	Let publishers export their own data from DFP and AdX	Publishers switching providers
Auction documentation	Publish technical documentation explaining how DFP selects winning bids, instead of open-sourcing the code	Publishers, auditors and the monitor
Google Ads non-discrimination	No preferential bidding into AdX or other Google tools because of common ownership, and no bidding directly into DFP	Rival exchanges
Scope	The obligations apply worldwide, not only in the United States	Publishers and rivals outside the US

The documentation, global scope and bid-data points come from AdExchanger's summary of the unsealed opinion, which also reports that the court declined to impose restrictions on Google's Display and Video 360 buying tool because it found an insufficient connection to the unlawful conduct. The Next Web reports that websites using DFP will no longer have to use AdX, which unwinds the tie at the heart of the liability finding.

Much of the package tracks what Google itself offered. In its remedies proposal of May 2025, Google committed to make real-time AdX bids available to rival publisher ad servers, to deprecate its Unified Pricing Rules so publishers could set different floors for different bidders, and not to use "first look" or "last look" for open-web display ads. The court's additions, notably the Prebid integrations, data export and the monitoring machinery, are what turn those commitments into an enforceable regime.

How the Prebid and interoperability remedies are meant to work

The interoperability remedies are designed to let a publisher use Google's demand without being locked into Google's ad server, and to let Google's ad server receive competing demand on equal terms. That is the practical meaning of Judge Brinkema's choice of access over separation.

Prebid is an open-source header-bidding framework that lets publishers invite several exchanges to bid for an impression at once, before the ad server makes its final decision. For years, AdX's strongest demand, from advertisers buying through Google Ads, reached publishers most easily when those publishers used DFP. Requiring AdX to integrate with Prebid, and to bid into rival publisher ad servers on terms functionally equivalent to those DFP enjoys, is meant to break that link. A publisher could, in principle, move to a competing ad server and still receive AdX bids.

The DFP to Prebid integration works in the other direction. It lets publishers who remain on Google's ad server run a genuinely open auction in which rival exchanges compete with AdX on visible terms. The requirement to publish documentation of DFP's auction logic, rather than open-source it, is the court's compromise on transparency: the government wanted the code itself released, and the court concluded that documentation would do.

The data remedies support switching. Real-time win and loss data tell a publisher how its inventory is actually clearing, and the right to export data from DFP and AdX lowers one of the classic switching costs in enterprise software. For technology, media and telecoms lawyers, the drafting of these technical obligations in the final judgment, including latency, data formats and timing, will decide whether they are usable in practice. Critics remain sceptical. Jay Friedman of CartographAI asked what a publisher should do if it wants a different ad server but still wants Google's buy-side demand, telling AdExchanger he did not think the court had provided a sufficient answer.

Why Judge Brinkema refused to break up AdX

Judge Brinkema refused an AdX divestiture because she concluded that it would be slow, risky and uncertain, while behavioural remedies could take effect quickly and give rivals the access the case was about. The Department of Justice and the states had argued that Google could not be trusted with continued ownership and that conduct rules would erode its monopoly slowly, if at all.

The opinion answers that argument directly. The judge wrote that although an AdX divestiture "seems like a simple and elegant antitrust remedy" in theory, the evidence showed that in reality it would be "incredibly messy and highly risky", and that "lack of trust alone" could not justify it, as quoted by the National Law Review. She reasoned that access to AdX's real-time bids through other ad servers would restore the competition that mattered, according to Reuters.

The outcome was foreshadowed at closing arguments on 21 November 2025. Courthouse News reported that the judge told the government "You haven't identified a potential buyer", observed that it was unlikely Google would not appeal, and stressed that time was of the essence in a market being reshaped quickly. The concern was that a divestiture could be held up for years by an appeal, while behavioural rules could start working sooner.

The government's structural package had three parts, Norton Rose Fulbright's review of the closing arguments explains: divest AdX, make DFP's final auction logic open source, and divest the rest of DFP if necessary. All three failed. That makes this the second time in 12 months that a US court has declined to break up Google after finding it a monopolist, following Judge Amit Mehta's September 2025 remedies decision in the search case, where the court instead banned exclusive distribution contracts and required data sharing.

The six-year monitor and technical committee

A monitor supported by a technical committee will oversee Google's compliance for six years under the final judgment, the Department of Justice said. That machinery, rather than a one-off divestiture, is what the ruling relies on to keep the new rules working.

According to AdExchanger's reading of the opinion, the court-appointed technical monitor will have full access to Google's employees, systems and source code. The Next Web reports that the court can extend the term if the remedies' goals are not met, which gives the monitor's reports real weight: a poor compliance record could lengthen supervision.

For compliance teams the concept of a monitor is familiar from US enforcement settlements. What is unusual here is the scale and technical depth of what must be monitored: live auction code, bidding logic and integrations used by a global industry. The monitor will need engineers as well as lawyers, and the parties will argue over access, confidentiality and escalation procedures when they draft the final judgment. Readers following US enforcement will note the contrast with the settlement route in the RealPage rent-setting software case, which the Justice Department resolved by settlement rather than after a contested remedies trial.

Practitioners in Washington DC antitrust practices will be watching three questions: who is appointed, how disputes between the monitor and Google reach the court, and whether rivals can bring complaints to the monitor directly.

What Google was found liable for in April 2025

Google was found liable on 17 April 2025 for unlawfully acquiring and maintaining monopoly power in two open-web display markets, publisher ad servers and ad exchanges, and for unlawfully tying DFP to AdX. The Department of Justice called it a landmark victory.

Simpson Thacher's analysis of the liability opinion sets out the key holdings:

• Markets. The court found a worldwide market for publisher ad servers, in which DFP held about 91%, and a market for ad exchanges, in which AdX held an estimated 55% to 65%.
• Section 2. Google willfully acquired or maintained monopoly power in both markets.
• Section 1 tying. Google unlawfully tied DFP to AdX through technical restrictions.
• Conduct. The court condemned "first look", which gave AdX priority over rival exchanges, "last look", which let AdX adjust its bid after seeing the best rival bid, and Unified Pricing Rules, which stopped publishers setting higher floors for AdX.
• Claims rejected. The plaintiffs failed to prove a separate market for advertiser ad networks, and the court held that Google's acquisitions of DoubleClick and AdMeld were not themselves anticompetitive.

Those limits shaped the remedy. Because the acquisitions were not condemned, unwinding them was harder to justify, and because the advertiser-side claim failed, the court declined remedies aimed at Google's buying tools that were not tied to the proven conduct. For abuse of dominance specialists, the case is a reminder that remedy scope follows liability scope closely in US monopolisation law.

How the case got here: 2023 to 2026

The case took three and a half years from complaint to remedy, which is fast by the standards of US monopolisation litigation. The timeline below draws on the Department of Justice, PPC Land and Courthouse News.

Date	Event
January 2023	DOJ and a coalition of states sue Google in the Eastern District of Virginia (No. 1:23-cv-00108)
September 2024	Liability bench trial before Judge Brinkema
17 April 2025	Liability opinion: monopolisation of two markets and unlawful tying
May 2025	Google publishes its behavioural remedies proposal
22 September 2025	Remedies trial begins
21 November 2025	Closing arguments on remedies
2 September 2026	Order rejects structural remedies; opinion filed under seal
16 September 2026	106-page memorandum opinion unsealed
2 October 2026	Deadline for the proposed final judgment

At the remedies stage the government's courtroom team was led by Julia Tarver Wood, senior litigation counsel in the Antitrust Division, and Matthew Huppert, while Karen Dunn led for Google, according to Courthouse News.

What is the current status of the Google antitrust case? Final judgment and appeal

As of 18 September 2026, the remedies opinion is public but no final judgment has yet been entered, and Google has said it will appeal. The parties must file a proposed final judgment by 2 October 2026, and AdExchanger reports that the remedies take effect 60 days after Judge Brinkema signs it.

Google's position is split. Lee-Anne Mulholland, its vice president of regulatory affairs, said on 2 September that Google was "very pleased the Court rejected the DOJ's proposal to break apart tools that help small businesses reach new customers and grow", Al Jazeera reported. But the company disagrees with the liability findings on Google Ad Manager and intends to appeal them to the Fourth Circuit.

The government has claimed victory while keeping its options open. Associate Attorney General Stanley E. Woodward Jr said the ruling "marks a significant victory for this Department's efforts to protect and restore competition", adding that the department would continue to review the opinion to consider its options, according to the DOJ release. A cross-appeal on the refusal to divest cannot be ruled out.

How long will an appeal take? An appeal to the Fourth Circuit in a case of this complexity is likely to take many months, and any petition to the Supreme Court would add more. Unless an appellate court stays the injunction, observers expect the behavioural obligations to begin to bite while the appeal runs, which is precisely why the judge preferred them to a sale. For clients with exposure to Google's platforms, advisers in the United States will be tracking the final judgment text closely, since that document, not the opinion, will define the obligations.

How the US ruling compares with Europe, the UK and Canada

The US court and the European Commission agree on the conduct but differ on the cure: Brussels has said that only a divestiture would address Google's conflicts of interest, while the US court has chosen conduct rules. The UK and Canada are further behind.

On 5 September 2025 the Commission fined Google €2.95 billion for abusing its dominance in ad tech since at least 2014, by favouring AdX within DFP, including by informing AdX in advance of the best rival bid, and by steering Google Ads and DV360 demand to AdX, Loyens & Loeff summarised. The Commission gave Google 60 days to propose a fix and signalled that divestiture might be needed. Google's November 2025 response offered publishers the ability to set different floor prices for different bidders and greater interoperability, but no divestment, The Current reported. The Commission published the public version of its decision in case AT.40670 in January 2026, according to PPC Land, and as of early September 2026 was still assessing Google's proposal after granting itself more time in March.

Jurisdiction	Authority	Stage at 18 September 2026	Structural remedy?
United States	DOJ and states, E.D. Va.	Remedies opinion unsealed; final judgment due	Rejected
European Union	European Commission	€2.95bn fine (Sept 2025); assessing Google's proposal	Still under consideration
United Kingdom	CMA	Statement of objections (Sept 2024); considering next steps	No decision
United Kingdom	Competition Appeal Tribunal	£13.6bn publisher collective claim certified (June 2024)	Damages only
Canada	Competition Bureau, Competition Tribunal	Application filed (Nov 2024); constitutional challenge dismissed (March 2026)	Sought by the Bureau

The CMA's case page says it issued a statement of objections on 6 September 2024 and has been considering next steps while monitoring international developments. In the Competition Appeal Tribunal, a £13.6 billion opt-out claim on behalf of UK publishers was certified in June 2024; claims of that kind depend heavily on third-party litigation funding in the UK. In Canada, the Competition Bureau asked the Tribunal in November 2024 to order Google to sell two of its ad tech tools and pay a penalty, and the Tribunal dismissed Google's constitutional challenge in March 2026.

For Brussels competition practitioners, the question is whether the Commission will now accept conduct commitments close to the US package or insist on separation. The EU courts have recently backed the Commission against Big Tech, as in Apple's DMA gatekeeper ruling, and the Commission's fining methodology, explained in our guide to how EU fines are calculated, gives it leverage. UK advisers and Canadian competition counsel will be asking the same question of the CMA and the Bureau.

Follow-on damages: publishers, rival ad tech firms and collateral estoppel

The remedies ruling does not compensate anyone, but the liability findings behind it are already doing heavy work in private damages litigation in New York. That is where Google's largest financial exposure now lies.

The multidistrict litigation In re Google Digital Advertising Antitrust Litigation (No. 1:21-md-03010) in the Southern District of New York includes Gannett, Mail Media and Emmerich Newspapers, and was joined in early 2026 by publishers including Vox, The Atlantic, Business Insider, McClatchy, Slate and Advance, Bloomberg Law reported. The court has approved a notice plan for a certified class of roughly 5,000 publishers that claim they were overcharged through AdX.

The critical procedural development is issue preclusion. Holland & Knight notes that the New York court applied collateral estoppel broadly, adopting the Virginia liability findings so that Google cannot relitigate monopoly power and anticompetitive conduct. Plaintiffs therefore need to prove causation and damages rather than wrongdoing, which raises both financial exposure and settlement pressure. Rival exchanges have sued too: OpenX filed in August 2025 and PubMatic in September 2025, Marketing Dive reported.

Google's appeal matters here. If the Fourth Circuit reversed the liability findings, the preclusive foundation of the damages cases would weaken. For New York litigators and litigation and dispute resolution counsel advising publishers, the timing of any appellate decision relative to damages trials is now a central strategic variable.

What the ruling means for publishers, advertisers and ad tech rivals

For publishers the ruling promises more choice and more data, but no immediate change in fees or ownership. Google Ad Manager remains a single product under one owner, and published accounts of the order describe no cap on AdX's fees, which Al Jazeera put at 20% of publishers' ad sales.

The practical gains depend on implementation. Digiday reported that many publishers had questioned whether a divestiture would help them much and cared more about interoperability and access to auction data; the ruling gives them both on paper. Rival supply-side platforms are cautiously positive. PubMatic said the adoption of behavioural remedies "should establish a level playing field for all market participants", in a statement to AdExchanger.

Advertisers should see fewer structural advantages for Google's own buying tools inside Google's own auctions, since Google Ads may no longer bid directly into DFP or favour AdX because Google owns it. Brands that buy through independent demand-side platforms may benefit if rival exchanges win more AdX-comparable inventory. Advertising law advisers should also note that the rules apply globally, so European and Asian publishers gain the same integrations as US ones.

Critics are unconvinced. Barry Lynn of the Open Markets Institute called the ruling proof that the US judiciary is abdicating its duty, The Next Web reported. With advertising accounting for roughly 73% of Alphabet's annual revenue, according to Reuters, the commercial stakes of how strictly the rules are enforced remain very high.

What competition counsel and in-house teams should do now

Counsel should treat the next 90 days, from the proposed final judgment to the date the remedies take effect, as the window to shape how the obligations work in practice. The opinion sets principles; the final judgment and the monitor's early decisions will set the detail.

1. Read the final judgment, not only the opinion. The text filed by 2 October will define technical terms such as "functionally equivalent" integration and the scope of data export.
2. Map your contracts. Publishers and ad tech providers should review Ad Manager terms, Prebid configurations and data rights to see where new options open up.
3. Plan for the monitor. Businesses with complaints about Google's compliance should prepare evidence and learn the monitor's intake process once it is set.
4. Assess damages positions. Publishers inside or outside the New York class should take advice on opt-out decisions, limitation periods and funding.
5. Watch Brussels. A Commission decision requiring divestiture would create a conflict with the US regime that multinational publishers and advertisers would have to manage.

The case also has lessons for transactional work. Remedies debates in merger control, such as the multi-jurisdiction review of Paramount Skydance and Warner Bros. Discovery, increasingly turn on whether conduct commitments can be monitored effectively. Businesses facing that question, or any exposure to the Google ad tech remedies, can find specialist competition advisers in our directory.

Frequently asked questions

What is the Google ad tech antitrust remedies ruling?

It is Judge Leonie Brinkema's decision on how to fix Google's illegal ad tech monopolies. On 2 September 2026 she rejected a forced sale of AdX and other structural remedies, and her 106-page opinion, unsealed on 16 September 2026, orders interoperability, data sharing and non-discrimination rules policed by a six-year monitor.

Does Google have to sell AdX?

No. The court rejected the Department of Justice's request to divest AdX, to open-source DFP's final auction logic and to divest the rest of DFP if needed. The judge found a divestiture would be messy and risky and that behavioural remedies could restore competition faster.

What remedies must Google implement?

Google must integrate AdX and DFP with Prebid, submit AdX bids to rival publisher ad servers on the same terms as DFP, share real-time bid data with publishers, let them export their data, document DFP's auction logic, and stop Google Ads favouring AdX or bidding directly into DFP. The rules apply worldwide.

How long will the antitrust monitor oversee Google?

Six years under the final judgment, according to the Department of Justice, with a monitor and a technical committee. The government had asked for 15 years. Reports of the opinion say the monitor will have access to Google's staff, systems and source code, and that the court can extend the term.

What was Google found guilty of in the ad tech case?

In April 2025 the court found Google unlawfully monopolised the markets for publisher ad servers and ad exchanges for open-web display advertising, in breach of Section 2 of the Sherman Act, and unlawfully tied DFP to AdX under Sections 1 and 2. A claimed advertiser ad network market was rejected.

What is the current status of the Google ad tech case?

As of 18 September 2026 the remedies opinion is public and the parties must file a proposed final judgment by 2 October 2026. The remedies are reported to take effect 60 days after the judgment is signed. Google has said it will appeal the liability findings.

Will Google appeal the ad tech ruling?

Yes. Google has said it disagrees with the court's decision on Google Ad Manager and will appeal, while welcoming the rejection of a break-up. The Department of Justice is reviewing its options. An appeal to the Fourth Circuit is likely to take many months, and the remedies may apply while it runs.

How does the US ruling compare with the EU adtech decision?

The European Commission fined Google €2.95 billion in September 2025 for similar self-preferencing and said divestiture might be the only answer. As of early September 2026 it was still assessing Google's conduct-based proposal, so the EU could still diverge from the US by requiring structural separation.

Can publishers claim damages from Google?

Yes. Publishers and rival ad tech firms are pursuing damages in the New York multidistrict litigation, where a class of about 5,000 publishers has been certified and the court has applied the Virginia liability findings through collateral estoppel. In the UK a £13.6 billion publisher claim is proceeding in the Competition Appeal Tribunal.

Sources

1. US Department of Justice: Department of Justice again wins substantial relief against Google (16 September 2026)
2. AdExchanger: The court just unsealed Judge Brinkema's remedies decision in the Google ad tech antitrust case (16 September 2026)
3. PPC Land: DOJ loses AdX divestiture bid as Brinkema accepts behavioral remedies (2 September 2026)
4. KELO (Reuters): Google should relax ad tech rules, appoint antitrust monitor, US judge finds (16 September 2026)
5. The Next Web: Judge's full ruling puts Google's ad tech business under a monitor for six years (17 September 2026)
6. National Law Review: Federal judge rejects DOJ request to force Google's AdX divestiture (17 September 2026)
7. AdExchanger: Google won't have to break up its ad tech business, Judge Brinkema rules (2 September 2026)
8. Al Jazeera: US judge rejects bid to break up Google's ad business (2 September 2026)
9. Google: Our remedies proposal in the DOJ ad tech case (May 2025)
10. Courthouse News: Judge signals hesitancy to divest Google's ad tech business (21 November 2025)
11. Norton Rose Fulbright: What you need to know from closing arguments in US v. Google (January 2026)
12. US Department of Justice: Department of Justice wins significant remedies against Google, search case (September 2025)
13. US Department of Justice: Department of Justice prevails in landmark antitrust case against Google (17 April 2025)
14. Simpson Thacher: District court rules Google is a monopolist in ad tech (25 April 2025)
15. Loyens & Loeff: European Commission fines Google EUR 2.95 billion over abusive practices in online advertising technology (September 2025)
16. The Current: Google offers ad tech changes to avoid EU-mandated divestment (18 November 2025)
17. PPC Land: European Commission releases public Google AdTech decision as structural remedies loom (14 January 2026)
18. The Next Web: Brussels said only a breakup would fix Google's ad tech (4 September 2026)
19. Competition and Markets Authority: Investigation into suspected anti-competitive conduct by Google in ad tech (case page)
20. Hausfeld: Multi-billion Google ad tech claim certified by UK Competition Appeal Tribunal (5 June 2024)
21. Competition Bureau Canada: Competition Bureau sues Google for anti-competitive conduct in online advertising in Canada (28 November 2024)
22. Competition Bureau Canada: Competition Tribunal dismisses Google's constitutional challenge (4 March 2026)
23. Bloomberg Law: Google's ad tech litigation defense grows as publishers pile on (3 February 2026)
24. Holland & Knight: Google ad cases show how binding government judgments shape MDLs (4 March 2026)
25. Marketing Dive: PubMatic sues Google as challenges to ad tech dominance mount (September 2025)
26. Digiday: Google avoided (yet another) breakup, now comes the test of the ad tech remedies (10 September 2026)

About this article

This analysis was researched and written by The Corporate INTL Newsroom, which covers cross-border legal, regulatory and business developments for lawyers, professional advisers and financiers in over 150 jurisdictions. It has been checked against the Department of Justice's statements, the court's order of 2 September 2026 as reported, reporting on the unsealed remedies opinion, law firm analysis of the April 2025 liability opinion, and the published positions of the European Commission, the CMA and the Competition Bureau. The final judgment had not been entered at the time of writing and its terms may differ in detail from the opinion. This article is general information, not legal advice; for advice on a specific matter, consult a qualified adviser. Last reviewed 18 September 2026. For more analysis like this, visit the Corporate INTL newsroom or subscribe to Corporate INTL.