The U.S. Department of Justice is preparing to ask a federal court to break apart Google’s dominant advertising technology business, escalating its antitrust fight against the tech giant on a second major front.
During a court hearing on May 2, government lawyers explicitly stated their plan to seek the divestiture of key Google ad services, following a judge’s determination that the company holds an illegal monopoly in parts of the online ad market. U.S. District Judge Leonie M. Brinkema, overseeing the case in Virginia, has scheduled a trial for September 22 to decide on appropriate remedies.
This development adds another layer of complexity to Google’s legal challenges, as it comes less than a year after the DOJ sought structural remedies, including the potential forced sale of the Chrome browser, in a separate antitrust case focused on Google’s search market dominance currently being heard in Washington D.C.
Publisher Tools and Ad Exchange in Crosshairs
The government’s focus in the ad tech case centers on the tools Google provides to website publishers for managing and selling ad inventory (known as publisher ad servers), and the marketplace connecting ad buyers and sellers in real-time auctions (ad exchange).
Judge Brinkema ruled on April 17, that Google illegally monopolized the market for publisher ad servers – specifically its DoubleClick for Publishers (DFP) suite – and the AdX ad exchange. Importantly, the judge found the government had not proven its case regarding Google’s alleged monopolization of advertiser-side tools. Google has stated it disagrees with the April 17 ruling and intends to appeal.
At the May 2nd hearing, DOJ lawyer Julia Tarver Wood argued that merely changing Google’s behavior wouldn’t suffice. The government plans to ask Judge Brinkema to order Google to sell off AdX entirely.
For the publisher tools, the DOJ proposes a phased approach: first, spinning off the component that runs ad auctions and making its underlying code open source, followed later by the divestiture of the remaining publisher-facing functions, like record keeping. Wood underscored the government’s view, stating, “To leave Google with ‘90 percent of publishers beholden to them is, frankly, too dangerous.’”
Google Pushes Back Against “Extreme” Measures
Google strongly contested the need for a breakup. Karen Dunn, representing Google, argued during the hearing that such a move lacks legal precedent and would be practically unworkable, potentially harming user privacy and security.
“It is very likely completely impossible, what they’re talking about,” Dunn asserted, adding that potential buyers for the complex technology would likely be limited to other “enormous tech companies,” and that important security protections would vanish. Instead of divestiture, Google has proposed alternative remedies focused on changing specific business practices and opening up its ad auction bidding system more for publishers.
This mirrors Google’s defense in the ongoing search monopoly remedies trial before Judge Amit P. Mehta. There, Google’s lead counsel John Schmidtlein called the DOJ’s push to sell Chrome “extreme” and “fundamentally flawed,” arguing Google achieved its market position through “hard work and ingenuity” and user preference, not illegal tactics. Schmidtlein also suggested the “message from the government has been loud and clear: Google should be punished.”
Pattern of Conduct Concerns Link Search and Ad Tech Cases
The government sees parallels between Google’s actions in search and ad tech. The DOJ has used the search remedies trial to highlight concerns that Google is using tactics similar to those deemed illegal in search – such as paying billions for default placements (reportedly $26.3 billion overall in 2021) – to establish dominance in the newer AI market.
Testimony revealed Google began paying Samsung “enormous sums of money” monthly in January 2025, plus sharing ad revenue, to preinstall its Gemini AI app. The structure of this deal, and a similar one with Motorola for its Razr phones, was presented by the DOJ as evidence that Google is employing the same playbook Judge Mehta found illegal in the search market.
While Google maintains these are standard competitive practices, the DOJ argues they represent a pattern of leveraging existing monopolies to gain unfair advantages.
“We’re here to restore competition to these markets,” DOJ lawyer David Dahlquist stated in the search trial, arguing that “The antitrust laws are designed to adapt to advances in technology, the oil companies and railroads of yesterday are the internet and search engines of today.”
The outcome of both the search and ad tech remedy proceedings, expected later this year and into 2026 respectively, could significantly reshape Google’s business structure and the competitive dynamics of the digital advertising and AI landscapes.
