A U.S. federal judge has ruled that Google violated antitrust laws by monopolizing key segments of the online advertising market, dealing a major development in the government’s ongoing push to rein in Big Tech’s dominance over digital infrastructure.
In a decision handed down by Judge Leonie Brinkema of the U.S. District Court in Alexandria, Virginia, the court found that Google “willfully acquired and maintained monopoly power” in the markets for publisher ad servers and ad exchanges—two foundational components of the digital advertising ecosystem.
These technologies are central to how online publishers sell ad space and how advertisers reach audiences across the web. The DOJ argued that by tying its publisher ad server to its ad exchange platform, Google created a closed loop that suppressed competition, harmed publishers and advertisers, and left consumers with fewer choices in how content is monetized and displayed online.
“For over a decade, Google has tied its publisher ad server and ad exchange together through contractual policies and technological integration,” Brinkema wrote, adding that these tactics enabled the company to entrench its dominance in the open-web display advertising market.
The court’s decision represents the second legal ruling confirming that Google maintains an unlawful monopoly, following a similar finding in a separate case involving its search engine business. However, the court dismissed a separate claim that Google controlled the advertiser ad network market.
While the ruling doesn’t immediately impose penalties, it paves the way for a future trial that could mandate structural remedies. The DOJ has indicated it may push for the breakup of parts of Google’s advertising business, such as requiring the sale of Google Ad Manager, which encompasses both its publisher ad server and ad exchange.
Google’s response to the ruling has been cautious. “We won half of this case and we will appeal the other half,” said Lee-Anne Mulholland, Vice President of Regulatory Affairs at Google. “We disagree with the decision regarding our publisher tools. Publishers have many options and choose Google because our ad tech tools are simple, affordable, and effective.”
Judge Brinkema also criticized the company for failing to preserve internal communications, noting that Google used a chat system that automatically deleted messages—a practice that raised concerns but did not affect the outcome of the case.
The ruling comes amid a broader antitrust reckoning for major tech firms. Meta, Amazon, and Apple are all facing similar scrutiny from U.S. regulators under both Democratic and Republican administrations. Legal analysts suggest that the outcome of these cases may signal a new era of structural intervention and tighter oversight in the digital economy.
As the DOJ and Google prepare for additional hearings—including remedy proposals and a separate search-focused trial in Washington, D.C.—this case could be a defining moment in shaping how digital markets are regulated and how far courts are willing to go in challenging Big Tech’s business models.
