DOJ wins antitrust fight against Google
Court rules tech giant illegally monopolized digital ad markets in major victory for prosecutors.
The U.S. Department of Justice secured a landmark victory against Google on Thursday, April 17, 2025, when a federal court ruled the tech giant illegally monopolized digital advertising markets.
In a significant win for federal antitrust enforcers, the U.S. District Court for the Eastern District of Virginia held that Google violated Section 2 of the Sherman Act by monopolizing open-web digital advertising markets. According to the Department of Justice, the ruling confirms that Google "harmed Google's publishing customers, the competitive process, and, ultimately, consumers of information on the open web."
"This is a landmark victory in the ongoing fight to stop Google from monopolizing the digital public square," said Attorney General Pamela Bondi in the Department's announcement. "This Department of Justice will continue taking bold legal action to protect the American people from encroachments on free speech and free markets by tech companies."
The case marks the second successful monopolization lawsuit the Justice Department has brought against Google. Just eight months earlier, in August 2024, a separate federal court ruled that Google had illegally maintained a monopoly in online search and search advertising markets.
The government's case
The Justice Department, together with Attorneys General from seventeen states, filed the civil antitrust suit against Google on January 24, 2023. According to court records, the government claimed Google had monopolized multiple digital advertising technology products in violation of Sections 1 and 2 of the Sherman Act.
Filed in the U.S. District Court for the Eastern District of Virginia, the complaint alleged that Google monopolized key digital advertising technologies that website publishers depend on to sell ads and that advertisers rely on to buy ads and reach potential customers. These technologies, collectively referred to as the "ad tech stack," are vital to publishers generating advertising revenue that supports content creation across the open web.
"Through this monopolization lawsuit, the Justice Department and state Attorneys General seek to restore competition in these important markets and obtain equitable and monetary relief on behalf of the American public," the Department stated in its original announcement of the lawsuit.
According to the complaint, over the past 15 years, Google engaged in a course of anticompetitive and exclusionary conduct that consisted of neutralizing or eliminating ad tech competitors through acquisitions; wielding its dominance across digital advertising markets to force more publishers and advertisers to use its products; and thwarting the ability to use competing products.
The Justice Department argued that Google used its control over the digital tool that nearly every major website publisher uses to sell ads (publisher ad server); the dominant advertiser tool that helps millions of large and small advertisers buy ad inventory (advertiser ad network); and the largest advertising exchange (ad exchange), a technology that runs real-time auctions to match buyers and sellers of online advertising.
Specific anticompetitive conduct
The court found that Google willfully acquired and maintained monopoly power through a series of anticompetitive acts. According to the Department of Justice, Google's anticompetitive conduct included:
- Acquiring competitors: Engaging in a pattern of acquisitions to obtain control over key digital advertising tools used by website publishers to sell advertising space.
- Forcing adoption of Google's tools: Locking in website publishers to its newly-acquired tools by restricting its unique, must-have advertiser demand to its ad exchange, and in turn, conditioning effective real-time access to its ad exchange on the use of its publisher ad server.
- Distorting auction competition: Limiting real-time bidding on publisher inventory to its ad exchange, and impeding rival ad exchanges' ability to compete on the same terms as Google's ad exchange.
- Auction manipulation: Manipulating auction mechanics across several of its products to insulate Google from competition, deprive rivals of scale, and halt the rise of rival technologies.
"Today's complaint alleges that Google has used anticompetitive, exclusionary, and unlawful conduct to eliminate or severely diminish any threat to its dominance over digital advertising technologies," Attorney General Merrick B. Garland stated when the lawsuit was filed.
Assistant Attorney General Abigail Slater of the Justice Department's Antitrust Division celebrated the ruling, stating: "The Court's ruling is clear: Google is a monopolist and has abused its monopoly power. Google's unlawful dominance allows them to censor and even deplatform American voices. And at the same time, Google destroyed and hid information that exposed its illegal conduct."
Key findings in the court's decision
After a three-week trial in September 2024, the court determined that Google had monopolized two distinct markets: the publisher ad server market and the ad exchange market for open-web display advertising. The judge found that Google possessed monopoly power in both markets and had willfully acquired and maintained that power through anticompetitive conduct.
According to the ruling, Google's publisher ad server, DoubleClick for Publishers (DFP), maintained a 91% market share globally, while its ad exchange, AdX, controlled between 54% and 65% of transactions in its market — approximately nine times larger than its closest competitor.
The court specifically identified Google's tying of its publisher ad server to its ad exchange as a key anticompetitive practice. By restricting real-time access to its ad exchange only to publishers using Google's ad server, Google effectively forced publishers to use both products together.
The Justice Department argued, and the court agreed, that this tying arrangement allowed Google to maintain its dominant position in both markets, driving nearly all competitors out of the publisher ad server market and securing a durable market share.
Significantly, the court rejected Google's defense that its conduct constituted legitimate product design choices made for valid business reasons. The judge determined that Google's proffered justifications of improved safety, privacy, reduced fraud, and decreased latency were either pretextual or substantially outweighed by the anticompetitive effects of its conduct.
Impact on digital publishing ecosystem
According to the Department of Justice, Google's monopolistic practices had profound consequences for the digital publishing industry and consumers. By controlling the infrastructure through which websites monetize their content through advertising, Google gained extraordinary power over how information is distributed and monetized online.
"The complaint filed today alleges a pervasive and systemic pattern of misconduct through which Google sought to consolidate market power and stave off free-market competition," said Deputy Attorney General Lisa O. Monaco when the lawsuit was launched. "In pursuit of outsized profits, Google has caused great harm to online publishers and advertisers and American consumers."
Associate Attorney General Vanita Gupta added: "We allege that Google has captured publishers' revenue for its own profits and punished publishers who sought out alternatives. Those actions have weakened the free and open internet and increased advertising costs for businesses and for the United States government, including for our military."
The case highlighted how Google's dominance affected revenue streams for online publishers, particularly news organizations and other content creators who rely on digital advertising to fund their operations. By extracting approximately 20% of advertising dollars flowing through its exchange while impeding competition, Google reduced the revenue available to fund digital journalism and other online content.
Next steps: Remedies to be determined
The court has yet to determine appropriate remedies for Google's antitrust violations. According to the Department of Justice, the trial was divided into two phases, with the first focusing on liability and the second to address remedies.
In the liability phase that just concluded, the court found Google liable for monopolization of the publisher ad server market, monopolization of the ad exchange market, and unlawful tying of its ad exchange and publisher ad server.
Potential remedies could include structural solutions, such as requiring Google to divest portions of its ad tech business, or behavioral remedies, such as prohibiting certain business practices and requiring greater interoperability with competing services.
"Today's decision follows a 15-day trial in September 2024 in the U.S. District Court for the Eastern District of Virginia," the Justice Department noted in its announcement of the victory. "In January 2023, the Justice Department, along with Attorneys General of several states and the Commonwealth of Virginia, filed a civil antitrust lawsuit against Google for monopolizing key digital advertising technologies."
Timeline of DOJ actions against Google
- January 24, 2023: The Department of Justice files civil antitrust lawsuit against Google for monopolizing digital advertising technologies
- September 2024: 15-day trial held in the U.S. District Court for the Eastern District of Virginia
- April 17, 2025: Court rules Google violated antitrust law by monopolizing open-web digital advertising markets
- August 5, 2024: In a separate case, court rules Google monopolized search and search advertising markets
- September 2023: Trial in the search monopolization case concludes
- October 2020: DOJ files its first monopolization case against Google focused on search
The Department of Justice prevailing in two major monopolization cases against Google in less than a year represents a significant shift in the enforcement of U.S. antitrust laws against dominant technology companies.
"Today's opinion confirms Google's controlling hand over online advertising and, increasingly, the internet itself," Assistant Attorney General Slater remarked. "I am extraordinarily proud of the dedicated public servants whose tireless efforts led to today's decision."