By Robert 
In a significant legal setback for Alphabet Inc., a U.S. federal judge has ruled that Google illegally held monopolies in key segments of the online advertising technology industry.
U.S. District Judge Leonie Brinkema, presiding in Alexandria, Virginia, concluded on Thursday that Google unlawfully dominated two major ad tech markets—publisher ad servers and ad exchanges, both crucial components of the digital advertising ecosystem. However, she found that prosecutors did not provide sufficient evidence to prove Google monopolized the advertiser ad network market.
The ruling marks a major win for the U.S. Department of Justice (DOJ) and a coalition of states, who have argued that Google’s dominance stifled competition and harmed both publishers and advertisers.
Breakup Could Be on the Table
Following this decision, the DOJ could now push for structural remedies, including a potential breakup of Google’s advertising business. Specifically, the DOJ has proposed that Google divest its Google Ad Manager suite, which includes both the publisher ad server and ad exchange.
If pursued, the ruling could set the stage for Google to face asset divestiture orders in two separate antitrust cases. In a separate proceeding starting next week in Washington, D.C., the DOJ will argue that Google’s Chrome browser and its dominance in online search should also be addressed through significant structural changes.
Google’s Defense: Competition Still Thrives
Google has long maintained that its advertising tools remain competitive. In court, the company argued that the DOJ’s case focused on outdated market conditions, and that it has since worked to improve interoperability between its ad tools and third-party systems.
Google also emphasized that other tech giants such as Amazon and Comcast are strong players in the rapidly evolving digital ad space, particularly as advertising shifts toward mobile apps and streaming platforms.
History of Monopoly Tactics, Prosecutors Say
The judge’s decision follows a three-week trial held last year. During the trial, prosecutors outlined how Google employed classic monopoly tactics, including:
- Acquiring rival companies to neutralize competition
- Locking in customers through tightly integrated ad products
- Controlling key parts of the ad transaction process
They argued this strategy helped Google maintain a stranglehold over how online ads are bought and sold—ultimately hurting competition and innovation.
More Legal Pressure Ahead
Google has reportedly considered selling parts of its ad business in Europe to appease regulators there, according to a Reuters report from September. However, the U.S. legal pressure is mounting, and the potential for court-ordered divestitures in multiple jurisdictions could force Google into a major restructuring of its ad empire.
The full impact of Judge Brinkema’s ruling will become clearer as enforcement measures are discussed and implemented in the coming months.