Google Faces Antitrust Trial Over Advertising Technology Monopoly

The U.S. Department of Justice (DOJ) is pursuing a significant antitrust case against Google, focusing on its alleged monopoly in online advertising technology. The trial, presided over by U.S. District Judge Leonie M. Brinkema in Alexandria, Virginia, commenced on September 22, 2025, and is expected to last two to three weeks. This case follows a previous ruling in which Judge Brinkema determined that Google had unlawfully maintained monopolies over its ad technology, specifically the tools used by publishers to sell ad space and the software connecting buyers and sellers.

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The DOJ has proposed that Google be compelled to sell its advertising exchange, AdX, and to open its auction mechanisms to competitors. Julia Tarver Wood, representing the DOJ, argued that these measures are necessary to restore competition, stating, “The purpose of a remedy is doing what is necessary to restore competition.” Conversely, Google’s legal team, led by Karen Dunn, contended that the DOJ's proposals are extreme and would disrupt the digital advertising ecosystem. Google has suggested alternative measures, such as making its ad exchange compatible with rival tools and adjusting auction rules to benefit publishers.

New York Times

This trial is part of a broader bipartisan effort to regulate major tech companies, which has gained momentum since the Biden administration. Earlier this month, a separate case involving Google’s search engine concluded with a ruling that spared the company from a breakup, instead requiring it to share search results with competitors. The outcomes of these cases could set precedents for future antitrust actions against other tech giants, including Meta, Amazon, and Apple.

New York Times

Critics of Google, including various publishers and rival ad tech firms, argue that the company's practices have stifled competition and innovation in the digital advertising market. They assert that Google’s control over both the publisher ad server and the ad exchange has allowed it to manipulate the market to its advantage, resulting in unfair pricing and limited options for advertisers and publishers.

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Google's Vice President of Regulatory Affairs, Lee-Anne Mulholland, stated that the DOJ's proposals would “unwind acquisitions the Court found to be lawful” and risk damaging tools that benefit advertisers and publishers. The DOJ has not provided additional comments on the matter but maintains that significant changes are necessary to rectify the competitive landscape.

Antitrust Trial: US Tells Court To Break Google’s Ad Business

While the DOJ claims that Google controls 87% of the U.S. ad-selling technology market, Google argues that the advertising landscape has evolved significantly, with increased competition from platforms like TikTok. The extent to which these changes impact the necessity for the DOJ's proposed remedies remains a point of contention.

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Judge Brinkema is expected to issue a ruling on the proposed remedies in the coming months, which could have profound implications for Google's business model and the digital advertising industry as a whole. The outcome of this trial will be closely monitored by stakeholders across the advertising ecosystem, as it may reshape the competitive dynamics in online advertising.

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• “Nothing short of a structural divestment is sufficient to bring meaningful change,” — Julia Tarver Wood, DOJ Lawyer

New York Times

• “The means to cheat are buried in computer codes and algorithms,” — Julia Tarver Wood, DOJ Lawyer

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• “We’ve said from the start that DOJ’s case misunderstands how digital advertising works and ignores how the landscape has dramatically evolved, with increasing competition and new entrants,” — Lee-Anne Mulholland, Google VP of Regulatory Affairs

Antitrust Trial: US Tells Court To Break Google’s Ad Business

• “If you get rid of the exchange, which is the connector between those two, you no longer tie the publishers in that respect, and the advertisers can go out and use any exchange that they want,” — Judge Leonie M. Brinkema

New York Times

This trial represents a critical juncture in the ongoing scrutiny of Google’s market practices and the broader implications for antitrust enforcement in the technology sector.

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