A federal judge has ruled that Google unlawfully monopolized key segments of the online advertising technology market, marking a major victory for U.S. antitrust authorities and clearing the path for possible structural remedies, including a breakup of Google’s ad tech business.
In a decision issued by Judge Leonie Brinkema of the U.S. District Court in Alexandria, Virginia, the court found that Google violated Sections 1 and 2 of the Sherman Act by tying its dominant publisher ad server (DoubleClick for Publishers, or DFP) with its ad exchange (AdX). The judge concluded that Google “willfully acquired and maintained monopoly power” in these two critical markets: publisher ad servers and ad exchanges.
While the ruling rejected the Department of Justice’s (DOJ) claim that Google held a monopoly in advertiser ad networks, it upheld core allegations that the company distorted competition in other parts of the ad tech ecosystem. The judgment allows the DOJ to move forward with remedies, potentially requiring Google to divest parts of its advertising technology stack—most notably its Google Ad Manager suite, which includes DFP and AdX.
The DOJ and a coalition of U.S. states argued that Google had engaged in anticompetitive conduct by acquiring rivals, restricting interoperability with competitors, and leveraging its position to favor its own services across the digital advertising supply chain. The case follows a three-week trial held in 2024.
Lee-Anne Mulholland, Google’s Vice President of Regulatory Affairs, stated that the company plans to appeal the decision. “We won half of this case and will appeal the other half,” she said. “We believe publishers choose Google because our ad tech tools are simple, affordable, and effective.”
Following the ruling, Google’s shares dropped by approximately 2.1% in midday trading.
The ruling sets the stage for a future court hearing to determine appropriate remedies. The DOJ has indicated that Google should be required to divest at least its ad server and exchange businesses to restore competitive conditions. A timeline for the next phase of proceedings has not yet been announced.
This case adds to Google’s growing regulatory challenges. Next week, a separate antitrust trial in Washington will address the DOJ’s request for the company to divest its Chrome browser and implement further changes to curb its dominance in online search.
Google previously considered selling its ad exchange business to satisfy concerns raised by European regulators, according to earlier reporting by Reuters.
