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Google keeps AdX under a six-year interoperability order
Judge Leonie Brinkema refused to order a sale of AdX and instead bound Google to six years of interoperability terms and an internal compliance monitor, over a unit the New York Times puts at about $30 billion a year.
The Investor · Invest desk
What happened
- A remedies ruling from Judge Leonie Brinkema, made public on September 16, binds Google's ad-tech business to six years of court-ordered rule changes and monitoring, Reuters reported.
- The court turned down the Justice Department's request to force a divestiture of AdX and disclosure of the source code behind Google's auction technology.
- The order also requires Google to appoint an internal antitrust compliance monitor for the duration of the remedy period.
- Google plans to appeal the liability findings tied to its publishing tools, after welcoming the court's refusal to break the ad stack apart.
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Why it matters
- capability A publisher that wants a different ad server no longer has to give up real-time AdX demand to get one, so switching becomes an integration expense it can quote and budget for.
- cost Six years of monitoring and compliance reporting is an operating charge carried by a unit the New York Times sizes at around $30 billion a year, and by the same teams building Google's next ad formats.
- contradiction The two revenue shares in circulation, 8 percent and 12 percent, cover differently defined units, so anyone reading a shrinking ad-tech business into the gap is comparing two things that were never the same.
- precedent A monopolization finding answered with interoperability terms and a monitor gives the next court a worked alternative to divestiture, and gives defendants a settlement shape to argue for.
The unit the Justice Department wanted carved out generated around $30 billion last year, about 8 percent of Alphabet's revenue, according to the New York Times [10]. Alphabet's advertising revenue in the second quarter of 2026 came in above $96 billion [12]. A full year of ad tech is therefore worth less than a third of one quarter of ad sales [16]. The 8 percent share implies annual Alphabet revenue near $375 billion [17].
Google is appealing the liability findings on its publisher tools even so [9]. Lee-Anne Mulholland, Google's vice president of regulatory affairs, told the New York Times: "We're very pleased the Court rejected the D.O.J.'s proposal to break apart tools that help small businesses reach new customers and grow." [8] Brinkema wrote that the measures "will be sufficient to effectively pry open to competition the ad tech markets that were injured by Google's unlawful conduct," according to Reuters [7]. Her April 2025 judgment found Google had unlawfully obtained a monopoly in parts of the publisher ad server and ad exchange markets [6].
The routing change has two operative terms. Google must stop conditioning use of its publisher ad server on AdX, and it must let real-time AdX bids work with competing publisher ad servers [4]. A publisher running a rival ad server can still take an AdX bid into the auction. The account of the ruling does not say how much of the publisher ad-server market Google holds today, and it says plainly that whether interoperability moves market share is hard to judge [19].
The remedies run six years [1]. OpenAI launched Sponsored Agents and natural-language campaign tools, with HubSpot and Shopify integrations, on September 16, the same day the ruling became public [13]. Google's own advertising roadmap runs to Gemini-built Conversational Discovery ads and AI-powered Shopping formats [14]. Gartner expects more than 70 percent of global ad spending, and 80 percent in the United States, to flow through AI-influenced self-serve platforms by 2028 [15].
If the Gartner figure is close, the order polices the link between a publisher ad server and an exchange [4] while a rising share of budget is placed in self-serve channels the remedy terms do not reach, and six years is long enough for that gap to compound. In my view the interoperability terms will change publisher contracts before they change spend. Two things cut the other way: a compliance monitor sitting inside the company for six years [5] can force default changes no outside plaintiff would win, and open-web display could hold its share better than the 2028 forecast implies. I would give up the view if rival publisher ad servers begin disclosing share gains won on real-time AdX access, or if Google's appeal removes the liability finding the remedies rest on [9].
What to watch
- Whether the compliance monitor's remit is written to cover new Gemini ad formats or only the existing publisher ad server and exchange.
- Whether Alphabet reports ad-tech revenue as its own line; without it, the $30 billion figure stays a press estimate.
- Whether the Justice Department appeals the refusal of structural remedies it asked for, including AdX divestiture.