DOJ Intends to Break-Up Googles' Ad Technology

The U.S. Justice Department (DOJ) On Friday outlined its intent to seek a breakup of Google’s advertising technology (ad tech) business during a hearing in the U.S. District Court for the Eastern District of Virginia, presided over by Judge Leonie M. Brinkema. 

This follows a landmark ruling on April 17, 2025, where Judge Brinkema found that Google illegally monopolized two key ad tech markets: publisher ad servers and ad exchanges. The DOJ’s push for divestiture marks the second major antitrust action against Google within a year, following a separate case targeting its search monopoly. If successful, these efforts could fundamentally reshape the $2 trillion tech giant, representing the most significant government-led corporate breakup since AT&T in the 1980s.

The DOJ is seeking structural remedies to restore competition in the ad tech market, including:

Divestiture of Ad Tech Components:

• Ad Exchange (AdX): The DOJ plans to ask Judge Brinkema to force Google to sell its ad exchange, which facilitates real-time transactions between publishers and advertisers. Google’s AdX holds at least 50% of the ad exchange market.
• Publisher Ad Server (DoubleClick for Publishers): The government intends to require Google to divest its publisher ad server, which controls over 90% of the market and is used by website publishers to manage ad space. The DOJ also wants Google to share the code for auction-running tools with competitors to foster competition.
• Phased Divestiture: Later, the DOJ may push for Google to sell additional publisher tools, such as those for record-keeping, to further dismantle its ad tech dominance.
• Data Sharing: The DOJ aims to compel Google to share real-time ad bidding data with rival ad tech firms, enabling competitors to improve their offerings and challenge Google’s dominance.
• Ending Anticompetitive Practices: The DOJ seeks to prohibit Google from tying its ad server and exchange together through contractual policies and technological integrations, practices Judge Brinkema ruled were exclusionary and harmful to competition.

The DOJ argues that Google’s control over the ad tech stack—encompassing publisher ad servers (>90% market share), ad exchanges (≥50%), and advertiser ad networks (~80% for Google Ads)—creates a monopolistic chokehold. This dominance allows Google to extract high fees (30–50% per ad transaction), reduce publisher revenues, inflate advertiser costs, and stifle innovation, ultimately harming consumers and the open web.

Google strongly opposes the DOJ’s proposals, arguing they are legally and practically flawed.  It plans to appeal both the April 2025 ad tech ruling and the August 2024 search monopoly ruling, signaling a protracted legal battle.

Potential Implications

• For Google: Divestiture of ad tech units, which generate ~10% of Google’s revenue ($8 billion quarterly), could disrupt its business model and weaken its dominance in digital advertising, where it holds a 29% U.S. market share.
• For the Industry: A breakup could foster competition, lower ad fees, and increase publisher revenues, potentially revitalizing the open web. However, it may also create short-term market instability as new players emerge.
• For Antitrust Enforcement: Success in this case, alongside the search monopoly case (where the DOJ seeks to divest Chrome), could set a precedent for tackling Big Tech monopolies, influencing cases against Meta, Amazon, and others.
• For Consumers: Reduced ad tech fees could lower advertising costs, potentially benefiting consumers through more accessible online content. However, Google warns that service disruptions could harm user experience.

Judge Brinkema will hold a remedies hearing in September 2025 to finalize penalties. The DOJ and Google will present detailed proposals, with the court’s decision expected to face appeals, potentially delaying implementation for years. The case’s resolution will likely influence the trajectory of U.S. antitrust policy and the digital economy.