Google avoids ad tech breakup as Judge rejects forced sale of AdX

Google will not be forced to sell its AdX advertising exchange after a federal judge rejected the U.S. Department of Justice’s push to break up part of the company’s ad tech business, opting instead for behavioral remedies intended to address competition concerns in the open-web advertising market.

U.S. District Judge Leonie Brinkema ruled that Google can retain AdX, despite finding last year that the company had illegally maintained monopolies in publisher ad servers and ad exchanges. The full remedies decision remains under seal and is expected to be released after a 14-day period allowing the parties to redact confidential information.

The decision follows Brinkema’s April 2025 ruling that Google had violated antitrust law through its conduct in the publisher ad server and ad exchange markets. The court found that Google unlawfully tied its publisher ad server to AdX and used its position across the ad tech stack to restrict competition.

The DOJ subsequently sought structural remedies, most notably requiring Google to divest AdX. The government had argued during the remedies phase that behavioral restrictions alone would not sufficiently address the competitive problems identified by the court and that Google could not be trusted to operate the exchange following its previous conduct.

Google opposed the proposed divestiture, arguing that separating AdX from its existing advertising infrastructure would be technically complicated and disruptive for publishers and advertisers. The company instead proposed changes to how its advertising products interact with competing services.

Brinkema ultimately rejected the forced-sale approach. While the detailed requirements have not yet been made public, the court indicated that Google will have to implement behavioral changes to its ad tech operations rather than separate AdX from the company.

Several measures proposed during the case provide an indication of what those restrictions could involve. Google previously offered to make real-time AdX bid information available to competing publisher ad servers, giving rival platforms greater access to pricing signals from Google’s exchange.

Google also proposed eliminating Unified Pricing Rules, which currently limit how publishers can establish different price floors for individual bidders within Google Ad Manager. Removing those restrictions would give publishers greater control over how different sources of advertising demand compete for inventory.

Another proposed change would prevent Google from using preferential “first look” or “last look” auction advantages to adjust bids based on information unavailable to competitors. Google has said it no longer uses those practices.

The remedies discussion has also included the possibility of integrating AdX with Prebid, the open-source header bidding framework widely used by publishers. Such an integration could allow AdX to compete alongside other exchanges within the same publisher auction environment rather than receiving differentiated access through Google’s own ad server. Google has indicated support for a proposal along those lines.

The court’s decision leaves intact the structure of Google Ad Manager, which combines Google’s publisher ad server, formerly known as DoubleClick for Publishers, with access to AdX. That relationship was a central issue in the government’s case because publishers using Google’s ad server also gained access to the advertising demand flowing through its exchange.

In her 2025 liability ruling, Brinkema found that Google’s uniquely large pool of advertiser demand contributed to AdX’s position in the market. The court concluded that restricting much of that demand to AdX meant publishers risked losing significant revenue if they chose not to use Google’s exchange.

During the remedies proceedings, however, Brinkema raised concerns about the potential consequences of separating the products. A forced divestiture could disrupt publishers that currently depend on Google’s infrastructure, particularly smaller publishers using its ad-serving technology without charge. Structural separation could also trigger a lengthy appeals process before any changes took effect.

The behavioral approach is intended to address Google’s competitive advantages without requiring an immediate restructuring of its advertising business. PubMatic, which competes with AdX in the supply-side advertising market, said following the decision that behavioral remedies could provide a faster route toward establishing a more level competitive environment.

Google welcomed the rejection of the DOJ’s divestiture proposal, while the Justice Department said it was pleased that the court had ordered substantial relief and was evaluating its next steps.

The decision is the second major U.S. antitrust case in which a court found that Google illegally maintained monopoly power but declined to impose the government’s preferred structural remedy. In Google’s separate search antitrust case, Judge Amit Mehta rejected the DOJ’s attempt to force the company to divest Chrome after previously finding Google maintained an illegal monopoly in online search.

For the digital advertising industry, the immediate outcome means AdX will remain part of Google’s ad tech stack. The more consequential changes will depend on the behavioral restrictions included in Brinkema’s full decision, particularly how they affect auction data, publisher pricing controls and the ability of competing ad servers and exchanges to access Google’s advertising demand.