Google is heading back to court—this time on the defensive. The tech giant says it will challenge an antitrust ruling that found it guilty of abusing its dominance in the online advertising space.
“We won half of this case and we will appeal the other half,” said Lee-Anne Mulholland, Google’s vice president of Regulatory Affairs.
That “other half” carries weight. On Thursday, U.S. District Judge Leonie Brinkema ruled that Google “willfully acquired and maintained monopoly power” in two critical markets: publisher ad servers and ad exchanges—key infrastructure that powers how digital ads are bought, sold, and delivered across the web.
According to the ruling, Google’s control wasn’t just strong—it was illegal. The court found that the company’s tactics, particularly tying the use of its ad exchange to its ad server, locked out competitors and harmed not just rival firms, but publishers and consumers.
“In addition to depriving rivals of the ability to compete, this exclusionary conduct substantially harmed Google’s publisher customers, the competitive process, and, ultimately, consumers of information on the open web,” Brinkema wrote.
The ruling has set off a chain of consequences. The U.S. Department of Justice is now pushing for a radical solution: a breakup. Specifically, it wants Google to sell off its Google Ad Manager, the umbrella under which both the ad server and exchange operate.
This is the second time in under a year that a U.S. court has declared Google a monopoly—first in search, and now in ads. What makes this one particularly potent is that it hits a core part of Google’s business model: advertising revenue.
And while the financial impact of this ruling may not shake the company’s bottom line immediately—Google’s shares only dipped 1.4%—the structural risk is enormous.
A second trial is expected, though a date hasn’t been set. That hearing could determine the full extent of penalties, including which assets Google may be forced to spin off to restore competition.
The DOJ’s case argued that Google used classic monopoly-building tactics: buying rivals, locking in clients, and manipulating how ad transactions happened.
While Brinkema cleared Google of wrongdoing related to past acquisitions like DoubleClick and AdMeld, she firmly rejected the company’s defence of its publisher tools.
Still, Google is holding its line. “Publishers have many options and they choose Google because our ad tech tools are simple, affordable and effective,” Mulholland said. The judge’s findings, however, suggest that those “choices” may not have been as free as the company claims.
The ruling has drawn praise from regulators and lawmakers. U.S. Attorney General Pamela Bondi called it “a landmark victory in the ongoing fight to stop Google from monopolising the digital public square,” adding, “This Department of Justice will continue taking bold legal action to protect the American people from encroachments on free speech and free markets by tech companies.”
Outside the courtroom, market analysts are watching closely. Michael Ashley Schulman, chief investment officer at Running Point Capital, described the ruling as a “major inflection point” for the broader tech industry.
He warned that it could “increase regulatory risk premiums across major tech stocks,” especially those with tightly integrated services like Amazon and Meta.
Those companies aren’t off the hook either. Meta is currently in court over alleged dominance in personal social networking. Apple and Amazon are facing similar battles over control of mobile ecosystems and online retail.
