U.S. Justice Department Calls for Breakup of Google’s Advertising Technology Monopoly
September 22, 2025 — Alexandria, Va.
The U.S. Justice Department has formally requested a federal judge to order the breakup of Google’s advertising technology business, marking a significant escalation in the government’s efforts to address what it calls the tech giant’s monopoly power online. The announcement came during the opening statements Monday at a hearing before Judge Leonie M. Brinkema of the U.S. District Court for the Eastern District of Virginia.
Background on the Case
Earlier this year, in April, Judge Brinkema ruled that Google had established a monopoly over critical tools that websites use to sell advertising space, as well as the software facilitating the connection between publishers and advertisers. Specifically, the judge found Google controlled 87 percent of the U.S. market for publisher tools, giving it a dominant position over ads sold across the internet on sites ranging from news outlets to recipe blogs.
The government launched its lawsuit in 2023, arguing that Google leveraged this dominance to capture a larger share of ad sales than would be possible in a competitive market. The complaint targeted three key components of Google’s ad technology platform:
- Publisher tools used to manage and host ad inventory
- Advertiser tools used to bid on ad space
- The ad exchange software that connects buyers and sellers
While Judge Brinkema found Google violated antitrust laws by monopolizing publisher tools and the ad exchange, she ruled the government had not proven monopolistic control over advertiser tools.
Government’s Proposal: A Structural Divestiture
In Monday’s hearing, Justice Department lawyer Julia Tarver Wood emphasized that only a structural divestment would restore fair competition. The government urges Judge Brinkema to require Google to sell off its ad exchange— the core software that connects publishers and advertisers—and to open up the computer source code behind the publisher tools to outside competitors.
“Nothing short of a structural divestment is sufficient to bring meaningful change,” Tarver Wood asserted in her opening statement, arguing that more modest changes would fail to dismantle Google’s entrenched market power.
Google Pushes Back Against Breakup
Google’s attorneys, led by Karen Dunn, described the government’s breakup demand as “radical and reckless,” cautioning against drastic remedies. The company proposed more limited reforms, such as enhancing interoperability by making Google’s ad exchange compatible with rival platforms and adjusting auction rules to level the playing field.
“These proposals are tailored, as law requires, to the complexities of ad technology,” Dunn said, framing Google’s approach as cooperative alternatives rather than a forced divestiture.
Potential Implications and Larger Context
This case represents one of the most aggressive challenges to a major tech company since recent antitrust actions against Google and others. Notably, earlier this month Google escaped a breakup in a separate internet search monopoly case. There, a federal judge declined to order the sale of Google Chrome, instead mandating that the company share search data with competitors and amend certain contracts.
Legal experts suggest Judge Brinkema may take a more forceful approach given the scale of Google’s control in advertising technology, leaving open the possibility of a breakup.
Bill Kovacic, former Federal Trade Commission chair, commented, “She could do something that was more aggressive. At a minimum, whatever is going through her mind, she has the opportunity to do more.”
Outcomes of this and related lawsuits—including forthcoming rulings against Meta, Amazon, and Apple—will serve as a major indicator of the government’s willingness and ability to challenge the dominance of tech giants in commerce and communication.
Testimony Supporting the Breakup
The hearing included testimony from industry voices supporting the government’s demand. Andrew Casale, president of Index Exchange, a competing ad exchange provider, testified that Google’s proposed data sharing and technology openness plans were insufficient to restore market competition.
Grant Whitmore, Vice President of Ad Tech at publisher Advance Local, echoed this sentiment, stating that dismantling Google’s control over ad tech would create a “more level playing field” for publishers and competitors alike.
Next Steps
Judge Brinkema’s hearing is scheduled to continue for two to three weeks, after which she is expected to issue a ruling on the appropriate remedies. The decision could fundamentally reshape how digital advertising operates on the web, potentially forcing Google to divest lucrative parts of its business.
This case underscores the increasing scrutiny facing major technology firms regarding their market power and raises critical questions about the future regulatory landscape governing digital platforms.
Reporters David McCabe and Cecilia Kang contributed to this article from the Albert V. Bryan Courthouse in Alexandria, Virginia.
