Google Keeps AdX — the Monopoly Finding Stands, the Remedy Doesn't

A federal judge rejected the U.S. Justice Department's bid to force Google to sell its AdX advertising exchange. Google keeps the business despite an earlier ruling that it illegally monopolized parts of the publisher advertising technology market. In the Google ad tech antitrust case, liability stands and only the remedy changed.

Behavioral Remedies Instead of Divestiture

U.S. District Judge Leonie Brinkema declined to require Google to sell AdX, the marketplace where publishers sell digital advertising inventory through real-time auctions. She adopted most of the behavioral remedies proposed by both sides instead.

The DOJ and a coalition of states had argued for divestiture after the court found Google unlawfully tied publishers using its ad server to the exchange.

The Monopoly Ruling Stands

The decision does not disturb Brinkema's April 2025 ruling that Google illegally monopolized markets for publisher ad servers and ad exchanges. The court previously found that Google's conduct harmed publishers, the competitive process and consumers by locking publishers into its advertising technology.

Google's Argument, and the Numbers

Google said a forced sale would be technically difficult, create a lengthy transition and ultimately harm customers. It also argued the DOJ's proposal differed from Google's own earlier offer to sell AdX during a European Union antitrust investigation.

Ad Manager accounted for roughly 4.1% of Google's revenue and 1.5% of operating profit in 2020, according to Wedbush research based on court documents. More recent figures were redacted.

Google shared a statement on X attributed to Lee-Anne Mulholland, Alphabet VP of regulatory affairs: "We're very pleased the Court rejected the DOJ's proposal to break apart tools that help small businesses reach new customers and grow."

What's Left for Publishers and Advertisers

The court upheld its finding that Google violated antitrust law but stopped short of the breakup the DOJ sought. Google's publisher ad tech business stays intact, governed by conduct rules rather than structural separation.

Practically, nothing about the plumbing changes. The paths between ad server and exchange remain; what changes is the set of behaviors Google must follow. Regulation settling into conduct rules rather than structural change echoes how Meta turned an $18B settlement into a competitive weapon. For advertisers, the changes worth preparing for are the ones platforms drive themselves — like display campaigns moving into Demand Gen.