Google must loosen restrictions across its Google Hit With Massive £5 Billion Lawsuit – Find Out If You’re Eligible to Claim and operate under an antitrust compliance monitor for six years after a U.S. federal judge imposed behavioural remedies designed to restore competition without ordering the company to sell its AdX advertising exchange.
U.S. District Judge Leonie Brinkema of the Eastern District of Virginia set out the measures in a 106-page remedies opinion unsealed on 16 September. The ruling follows her April 2025 finding that Google unlawfully maintained monopoly power in the open-web display publisher ad-server and ad-exchange markets and illegally tied its DoubleClick for Publishers product, now part of Google Ad Manager, to AdX.
The Department of Justice had sought a structural remedy requiring Google to divest AdX, arguing that behavioural restrictions would not adequately address the competition problems identified at trial. Brinkema rejected that request, concluding that changes to Google’s business practices could provide sufficient access for competing ad-tech providers. The government had also sought restrictions lasting 15 years, but the final measures will operate for six.
Among the most significant requirements, Google must support integrations between AdX and Prebid and between DFP and Prebid, while AdX will also be required to submit real-time bids to competing publisher ad servers. The measures are intended to reduce the technical advantages created by Google’s ownership of multiple parts of the advertising technology stack.
Publishers must also be able to access and export their own data from Google’s DFP and AdX systems, making it easier to change technology providers. Google’s AdWords business will be prohibited from favouring AdX or other Google-owned ad-tech tools because of their common ownership, and AdWords will not be permitted to bid directly into DFP.
Brinkema also ordered the appointment of a monitor and technical committee to oversee Google’s compliance. The six-year regime will involve court-supervised monitoring of the company’s implementation of the remedies, although the oversight is narrower than the Department of Justice had proposed.
The case, United States et al. v. Google LLC, number 1:23-cv-00108, was brought by the Department of Justice and a group of U.S. states under the Sherman Act. Brinkema found after a three-week liability trial that Google had violated Section 2 by acquiring and maintaining monopoly power in two ad-tech markets and had unlawfully tied its publisher ad server and exchange in violation of Sections 1 and 2.
Google has said it disagrees with the liability ruling concerning Google Ad Manager and intends to appeal. The company has argued that forcing a divestiture would have damaged publishers and advertisers, particularly smaller businesses using its integrated advertising products.
Google’s defence during the liability proceedings was led by Karen Dunn of Paul, Weiss, Rifkind, Wharton & Garrison, while Julia Tarver Wood led the Department of Justice’s trial team. The Department of Justice has described the remedies ruling as significant relief, particularly because of the interoperability, data-sharing and non-discrimination requirements.
Associate Attorney General Stanley Woodward Jr said the department was reviewing the opinion and considering its next legal steps. The final judgment will incorporate the behavioural restrictions and compliance structure ordered by the court.
The ruling leaves Google in control of AdX but subjects the business to Google Faces EU Antitrust Penalty Under Digital Markets Act intended to reduce the advantages created by ownership of multiple parts of the advertising technology stack. For competition lawyers and in-house counsel, the decision is notable for the court’s choice of interoperability, data access and court-supervised monitoring rather than divestiture as the mechanism for addressing an established technology-market monopoly.
It also provides a significant example of how behavioural remedies can be structured around digital platforms whose products are technically interconnected. The effectiveness of those measures will now depend on implementation, the work of the monitor and technical committee, and the outcome of CJEU Confirms Google’s €4.1bn Android Fine — Lawyer Monthly.