A U.S. federal judge has ruled that Google illegally monopolised key digital advertising markets, siding with the Department of Justice and 17 state attorneys general in a case that could reshape the tech giant’s core business.
In a 115-page opinion released Thursday, U.S. District Judge Leonie Brinkema found that Google violated antitrust laws by “willfully acquiring and maintaining monopoly power” in two crucial markets: the publisher ad server market and the ad exchange market. The decision exposes Google to potential structural remedies, including forced divestitures.
“Google has willfully engaged in a series of anticompetitive acts to acquire and maintain monopoly power,” Judge Brinkema wrote. “This exclusionary conduct substantially harmed Google’s publisher customers, the competitive process, and, ultimately, consumers of information on the open web.”
What the case was about
The U.S. Department of Justice and multiple states brought the case in January 2023, alleging that Google used its dominant position to suppress competition in the tools used to buy and sell display advertising across the open web.
Central to the case was Google’s control over three key parts of the “ad tech stack”:
- Its publisher ad server, known as DoubleClick for Publishers (DFP), used by websites to manage ad inventory;
- Its ad exchange, called AdX, which matches buyers and sellers in real-time auctions;
- And AdWords, the advertiser-facing component of the Google Display Network.
The plaintiffs successfully proved that Google used its dominance across these tools to self-preference its own products, tie services together, and disadvantage rivals—while failing to show Google had a monopoly in advertiser ad networks.
In one example cited by the court, Google effectively required publishers using its ad server (DFP) to also use its ad exchange (AdX), locking out rival exchanges. At the same time, it limited access to AdWords demand to those using AdX, depriving other ad exchanges of crucial advertising spend.
Judge dismisses advertiser market claim
While the court found in favour of the government on two key counts—monopolisation of the publisher ad server and ad exchange markets—it dismissed the claim that Google monopolised the market for advertiser ad networks.
Google’s Vice President of Regulatory Affairs, Lee-Anne Mulholland, emphasised this in the company’s response:
“We won half of this case and we will appeal the other half,” she said. “The Court found that our advertiser tools and our acquisitions, such as DoubleClick, don’t harm competition.”
What happens next
The ruling does not itself impose penalties, but it clears the way for a remedies phase. The Department of Justice is seeking structural relief, including potentially forcing Google to divest Google Ad Manager, which comprises both DFP and AdX.
The decision comes just as a separate federal judge is preparing to hear closing arguments in a different DOJ case targeting Google’s search business. There, the DOJ is seeking to break off Google’s Chrome browser and halt its lucrative search distribution deals.
The Virginia case was decided following a three-week bench trial and extensive post-trial briefing. The court found that Google’s practices had not only harmed rivals but also diminished innovation, reduced revenues for publishers, and ultimately harmed consumers through less accessible and diverse online content.
The judge also criticised Google for “systemic disregard of the evidentiary rules” and its “misuse of the attorney-client privilege” in relation to evidence spoliation—suggesting the court may have imposed sanctions if the outcome had not been otherwise determinable from available testimony.
Wider implications for Big Tech
The ruling could have sweeping consequences not just for Google but for the broader tech sector. Regulators in the U.S., Europe, and Asia are increasingly scrutinising tech platforms for self-preferencing and bundling practices.
Michael Ashley Schulman of Running Point Capital described the decision as a “major inflection point,” adding that courts now appear open to “aggressive structural remedies.”
Other antitrust actions are progressing in parallel:
- Meta Platforms is defending itself against allegations it illegally maintained a monopoly in personal social networks.
- Amazon faces a case targeting its control of online retail markets.
- Apple has been sued for allegedly monopolising smartphone markets.
In Japan, regulators this week issued their first-ever cease-and-desist order against Google, finding the company violated local anti-monopoly laws by requiring manufacturers to pre-install Google apps on Android phones.
Market reaction
Alphabet shares fell 3.2% following the announcement. Analysts believe that while the financial hit from a breakup of its ad stack may not be immediate, any forced separation of core ad infrastructure would compromise Google’s integrated model—and potentially raise regulatory risk premiums across the tech sector.
“Google is now an illegal monopolist twice over,” said former DOJ antitrust chief Jonathan Kanter, who praised the ruling as a “huge victory for antitrust enforcement, the media industry, and the free and open internet.”
