Judge Rejects Google Ad Tech Breakup in Antitrust Ruling

U.S. District Judge Leonie Brinkema has rejected the Justice Department’s request to force Google to sell its AdX online advertising exchange, marking the second time in a year the company has avoided a court-ordered divestiture despite being found to operate an illegal monopoly [1, 2]. While the ruling spares Google from a structural breakup of its ad tech business, the court ordered the company to adopt behavioral remedies intended to curb practices that depress ad rates for web publishers [1, 3].

The court’s decision

The ruling follows Judge Brinkema’s April 2025 determination that Google violated the Sherman Act by dominating both the publisher ad server market and the ad-exchange market [2]. The Justice Department had argued that forcing a sale of AdX—the marketplace where Google collects a 20% fee on real-time ad auctions—was the only way to restore competition [1, 2]. Instead, the court opted to accept "most" of the behavioral changes proposed by both the government and Google, which include requirements for the company to share more information with publishers [1, 3].

The decision mirrors a separate antitrust case from last September, where U.S. District Judge Amit Mehta similarly declined to force the sale of Google’s Chrome browser after finding the company held a monopoly in the online search market [2]. In both instances, the courts have favored behavioral oversight over the structural dismantling of Google’s business units [1, 2]. Google’s VP of Regulatory Affairs, Lee-Anne Mulholland, stated the company is "very pleased" that the court rejected the proposal to break apart its tools [1, 2].

Market and regulatory response

The ruling has drawn sharp criticism from advocacy groups, with the Tech Oversight Project describing the decision as an "Olympic level of mental gymnastics" given the court’s earlier finding that Google’s conduct "substantially harmed" publishers [2]. Critics argue that these behavioral remedies are insufficient to address the company's market power, pointing to evidence that Google destroyed internal communications—referred to as "Vegas mode"—during the lead-up to the trial [2].

The Justice Department’s antitrust division expressed a more measured response, stating it was pleased the court ordered "substantial relief" despite the rejection of a breakup [2]. Associate Attorney General Stanley Woodward noted that the order reflects a trade-off between immediate relief and the remedies achievable through litigation [2]. The court also denied a request from the government to force Google to publish the source code governing the logic behind its AdX auctions [2].

What to watch

• Full Opinion Release: The court is expected to release the full, redacted opinion later this month, which will clarify the specific behavioral remedies Google must implement [2].
• Remedy Implementation: Monitor the timeline for when Google begins sharing additional data with publishers and how those changes impact ad auction transparency [1, 3].
• Legislative Action: Watch for potential pressure on Congress to pursue new antitrust legislation, as critics of the ruling have cited these court decisions as evidence that existing laws are insufficient to address Big Tech monopolies [2].

The open question remains whether behavioral mandates can effectively alter market dynamics in the absence of structural change. With the court’s full opinion still pending, the long-term impact on Google’s 20% ad exchange fee and its relationships with web publishers remains to be seen [1, 2].