Federal judge rules Google must ensure ad tech tools interoperate with rivals

Google just dodged the biggest bullet in its corporate history. US District Judge Leonie M. Brinkema ruled that the tech giant does not have to sell off its advertising exchange, AdX, rejecting the Department of Justice’s push for a structural breakup of Google’s ad tech business.

What the court actually decided

The ruling, handed down on September 2, follows an April 2025 finding where Judge Brinkema concluded that Google had illegally monopolized two critical markets: ad servers and ad exchanges. That earlier decision established that the company engaged in practices restricting competition and harming publishers.

The DOJ wanted the nuclear option. Prosecutors argued that Google should be forced to divest AdX, the real-time auction platform that charges publishers a 20% fee and sits at the center of how digital ads get bought and sold across the internet.

Judge Brinkema said no. Instead of ripping apart one of the most profitable advertising machines ever built, the court opted for behavioral remedies, essentially requiring Google to make its ad tech stack interoperable with rival platforms.

Google announced plans to appeal the underlying April 2025 liability ruling, which found it had maintained an illegal monopoly in the first place.

The scale of what’s at stake

Google’s advertising revenue hit approximately $294 billion in 2025. The ad tech division represents roughly 12% of Alphabet’s total revenue.

AdX charges publishers a 20% fee for real-time ad auctions. The DOJ compared Google’s integrated position — controlling the ad server, the exchange, and the buying tools — to owning the New York Stock Exchange while simultaneously being the biggest buyer and seller of stocks on it.

What interoperability actually means in practice

Both parties must submit a joint final judgment proposal within 30 days of the court’s decision. Major aspects of the remedies document are currently under seal for 14 days to allow for redactions.

In practical terms, interoperability likely means that competing ad exchanges and ad servers will need to be able to plug into Google’s ecosystem more easily. Publishers who use Google’s ad server might gain the ability to route their inventory through non-Google exchanges without friction or penalty.

Google’s simultaneous appeal of the liability finding adds another layer of uncertainty, since a successful appeal could render the entire interoperability framework moot.

Disclosure: This article was edited by Editorial Team. For more information on how we create and review content, see our Editorial Policy.