Alphabet’s Google is set to fight a potential forced sale of part of its online advertising business as a U.S. antitrust trial begins Monday in Alexandria, Virginia.
The case represents the government’s latest effort to challenge Google’s dominance in online advertising after a recent court ruling blocked a separate attempt to force the company to sell its Chrome browser. Online publishers and rival ad tech firms, some of whom have filed separate lawsuits against Google, will be closely monitoring the proceedings.
The U.S. Department of Justice (DOJ) and a coalition of states aim to compel Google to sell its ad exchange, AdX, which charges publishers a 20% fee to run instant ad auctions when users load websites. They also want the mechanism that determines auction winners to be made open source.
U.S. District Judge Leonie Brinkema, presiding over the trial, previously ruled in April that Google holds unlawful monopolies in web advertising technology. After this trial, she will decide what remedies, if any, to impose.
Google has asked Brinkema to adopt a cautious approach similar to that taken by a Washington, D.C., judge who recently rejected most of the DOJ’s remedies in a separate online search monopoly case.
The lawsuits are part of a broader bipartisan effort to rein in big tech, initiated during former President Donald Trump’s term, with ongoing cases against Meta, Amazon, and Apple.
Google argues that the DOJ’s proposed remedies are technically unworkable and could create prolonged uncertainty for advertisers and publishers. The company had previously considered selling AdX during private negotiations with the EU to resolve an antitrust inquiry, according to Reuters, and internal studies on that potential sale may be introduced at trial.
Instead of selling AdX, Google has proposed policy changes aimed at making it easier for publishers to use and support competing platforms. The DOJ maintains that these measures alone would not sufficiently restore competition.
Executives expected to testify include former News Corp officials and representatives from DailyMail.com and Advance Local, which operates local news outlets in eight states. Some witnesses previously testified when the DOJ argued that Google unlawfully tied its publisher ad server—a tool for managing digital ad inventory—to AdX, effectively locking publishers into its system.
According to Brinkema’s April ruling, this practice allowed Google to favor its own advertisers by giving them first and last bidding opportunities, disadvantaging publishers. The DOJ has also stated in court filings that if competition does not improve within four years, Google should be required to sell its publisher ad server as well.
