Although a second landmark antitrust case has been brought against Google, it is unclear how significant any remedies will be under the big tech-backed US administration
A US judge has ruled that Google holds an illegal monopoly in online advertising technology markets
On 17 April 2025, a US District Court ruled that Google is maintaining an illegal monopoly in two different online advertising markets. The suit, challenging Google’s dominance of the ad tech stack, was brought by the US Department of Justice (DOJ) and joined by 17 US attorneys general. Judge Leonie Brinkema of the US District Court for the Eastern District of Virginia found that Google has willfully engaged in a number of anticompetitive actions to acquire and maintain its monopoly power. This decision follows another US District Court ruling from August 2024 that found Google is an illegal monopolist in the online search market. Lee-Anne Mulholland (Vice President of Regulatory Affairs, Google) confirmed that the firm will appeal the ruling, claiming that “publishers have many options and they choose Google because our ad tech tools are simple, affordable and effective”.
Although Google’s “exclusionary conduct” harmed the competitive process, it has not been ruled as a monopolist in all aspects of the ad tech market
In her decision, Brinkema found that Google not only deprived its rivals of the ability to compete but also harmed its publishing customers, the overall competitive process and consumers through its “exclusionary conduct”. Brinkema ruled that Google had willfully monopolised the technology online publishers use to sell ad space and the largest exchange on which businesses bid for ads – two of the key elements of the ad tech stack. However, Brinkema found that the DOJ was unable to prove that Google had also unfairly monopolised the third key element of the ad tech market, advertiser ad networks. She made the point that the DOJ’s use of the term “advertiser ad networks” was not common in the industry and excluded publishers. As a result, Mulholland added in Google’s response that the firm had “won half” of the case.
The DOJ argues that Google must sell one of its primary online advertising platforms to rebalance competition
Although this case has not advanced to a further hearing to determine remedies, the DOJ has already called for Google, at a minimum, to be made to sell its Google Ad Manager platform to address how it essentially does business with itself throughout the ad tech stack. This recommendation could go further though, adding to ongoing efforts to break up Alphabet, Google and its other various subsidiaries such as Chrome in the firm’s other ongoing US antitrust case. As the ad tech case against Google begins to move towards the remedies phase, more specific demands about potential structural changes to Alphabet and Google will likely be established. At this early stage it is unclear whether both or either judges ruling in Google’s cases will agree with the structural remedies that are suggested, but given the DOJ’s calls for a divestment from Chrome in Google’s online search case, there is no doubt that there is potential for large-scale changes.
Regulators in the US, the EU and the UK are all considering the need to impose structural remedies to address Google’s dominance in digital ads
As yet another landmark antitrust case is brought against Google’s dominance in online advertising services, it is clear that regulators, not just in the US, are keen to pursue significant structural market changes to combat monopolies and enhance competition through ex-post regulation enforcement. In Europe, the EC has continued with its case against Google’s monopoly in ad tech under EU antitrust rules and in its preliminary findings, argued that the only way to address the competition issues identified is to enforce the mandatory divestment by Google from part of its services, aligning with the DOJ’s position in the US. Similarly, in Canada, the Competition Bureau’s investigation into Google’s conduct in the ad tech market has led to a lawsuit in which the Bureau is proposing the firm sell off two of its ad tech services to remove structural conflicts of interest. In the UK, the CMA is also using ex-post enforcement to investigate Google’s ad tech dominance under the 1998 Competition Act. Whether these cases and investigations will lead to significant structural changes to Alphabet and Google remains to be seen, especially in the US under the Trump Administration that has so far championed US big tech firms, lamenting those who attempt to constrain their dominance through regulation.
