DOJ Wins Google Ad Tech Antitrust Trial

On April 17, 2025, U.S. District Judge Leonie Brinkema of the Eastern District of Virginia ruled in United States et al. v. Google LLC that Google violated Section 2 of the Sherman Antitrust Act. The court found that Google had willfully acquired and maintained monopoly power in three key markets within open-web display advertising: publisher ad servers (with Google holding about 90% market share), ad exchanges (about 50% share), and advertiser ad networks (about 50% share). The judge determined that Google’s anticompetitive conduct included strategic acquisitions (such as DoubleClick in 2008 and AdMeld in 2011), product tying (e.g., requiring publishers to use Google’s AdX exchange with its DFP ad server), exclusive dealing arrangements, and manipulative auction practices that disadvantaged competitors and inflated costs for advertisers and publishers. This conduct harmed competition by creating barriers to entry, reducing innovation, and enabling Google to extract supracompetitive fees (estimated at 30-36% per transaction). The ruling emphasized Google’s dominance in the “ad tech stack,” which processes trillions of ad impressions annually, but did not find liability in a fourth alleged market for indirect advertiser buying tools.

The decision followed a bench trial that began in September 2024 and lasted 15 days, with closing arguments in November 2024. It marks the second major antitrust loss for Google in less than a year, following a separate ruling on its search monopoly.

Remedy Trial Timeline

The remedies phase, which will determine how to address Google’s anticompetitive behavior, is scheduled to begin as a bench trial on September 22, 2025, in the same court before Judge Brinkema. Both parties proposed this date shortly after the liability ruling, and it was confirmed by the court in early May 2025. The trial is expected to focus on evidence and arguments for specific remedies, with a decision potentially following in the months after.

Proposed Remedies to Resolve the Judge’s Concerns

The remedies aim to dismantle Google’s integrated ad tech monopoly, restore competition, and prevent future anticompetitive practices as outlined in the ruling (e.g., tying, exclusive deals, auction manipulation, and data advantages). Proposals from the U.S. Department of Justice (DOJ) and plaintiff states are more aggressive, emphasizing structural changes, while Google’s counterproposals focus on behavioral adjustments. Key proposals include:

• DOJ and States’ Proposals (Structural and Behavioral Remedies):
  • Divestiture of Key Assets: Force Google to sell off significant portions of its ad tech business, such as Google Ad Manager (which includes the DFP ad server and AdX exchange). This would break up the “walled garden” that gives Google end-to-end control over ad transactions.
  • Data and Bidding Restrictions: Ban Google from using first-party data from its own products (e.g., YouTube, Search, or Android) to gain unfair advantages in ad bidding or pricing. This addresses concerns about Google’s ability to leverage its ecosystem for preferential treatment.
  • Auction and Pricing Reforms: Prohibit manipulative practices like “last look” advantages in auctions (where Google could adjust bids after seeing competitors’) and require fair, non-discriminatory auction rules to prevent rigging.
  • Interoperability and Non-Exclusivity: Mandate that Google’s tools be compatible with rivals’ products, end exclusive contracts with publishers and advertisers, and allow easier switching to competitors.
  • Oversight and Compliance: Implement monitoring by a court-appointed trustee for up to 10 years, with potential fines for violations.
• Google’s Counterproposals (Primarily Behavioral):
  • Avoid divestitures, arguing they exceed the scope of the ruling and could harm innovation and users. Instead, propose tweaks to auction mechanics (e.g., “rigging ad auctions a little less”) and limited changes to product tying without breaking up assets.
  • Focus on transparency enhancements, such as better data sharing with competitors or minor adjustments to fee structures, to mitigate monopoly effects without structural separation.

The DOJ argues that behavioral remedies alone have proven insufficient in past cases (e.g., Microsoft’s antitrust settlement), necessitating divestitures to fully resolve the integration that fueled Google’s monopoly. The court will weigh these during the September trial, with potential appeals likely regardless of the outcome.