Court papers filed this week show that the US Department of Justice (DoJ) is seeking to force Google to divest its advertising exchange business, which it sees as a “critical instrument” of the search engine giant’s anti-competitive scheme.
In January 2023, the Justice Department, along with attorneys general of several states and the Commonwealth of Virginia, filed a civil antitrust lawsuit against Google for monopolising key digital advertising technologies – referred to as the “adtech stack” – that website publishers depend on to buy and sell adverts that reach millions of customers.
On 17 April 2025, the US District Court for the Eastern District of Virginia ruled that Google had violated antitrust law by monopolising open web digital advertising markets.
The court stated that Google “harmed Google’s publishing customers, the competitive process and, ultimately, consumers of information on the open web”.
Commenting on the court ruling, assistant attorney general at the Justice Department’s Antitrust Division, Abigail Slater, said: “Google’s unlawful dominance allows them to censor and even de-platform American voices. And at the same time, Google destroyed and hid information that exposed its illegal conduct.”
The DoJ wants Google to divest its adtech business, which Google claims is unworkable. In a court document covering its proposal for remediation, Google said its infrastructure is unique to its internal products. It said that no other commercially available or proprietary software infrastructure functions in the same way and claimed its adtech tools – such as Ad Exchange (AdX) and Doubleclick for Publishers (DFP) – would need to be rebuilt to work within a new software infrastructure that can perform the essential functions that Google’s proprietary, company-wide software infrastructure currently does.
Responding to the remedy proposed by the DoJ, Lee-Anne Mulholland, vice-president of regulatory affairs at Google, said in a blog post: “We are offering a proposal that fully addresses the court’s findings. These remedies would make it even easier for publishers to use Google Ad Manager with other adtech providers, while minimising disruption.”
Mulholland said Google would make real-time bid amounts for open web display ads from AdX available to all rival publisher ad servers and would deprecate unified pricing rules for open web display ads. According to Mulholland, this would enable publishers to set different price floors for different bidders when using Google Ad Manager. She said Google would also commit to not using “first look” and “last look” for open web display ads.
Rather than divesting its adtech business, expert witness Adam Epstein, co-CEO and president of adMarketplace, who has been working behind the scenes with the DoJ over the past year and testified during the trial, sees benefit in Google being forced to be more open.
Discussing the case with Computer Weekly, he said: “Google has a tremendous amount of data. It has tremendous engineers who have built phenomenal products. There’s no doubt about any of those things, and if Google licenses some of these things, we can create new and differentiated products on top of them, which would unlock a lot of value for consumers, advertisers and publishers.”
Specifically, Epstein would like access to an application programming interface (API) for partial query suggestions that occur when a user starts typing something into the Chrome browser address bar. This would enable alternative providers to take advantage of the scale that Google has built to deliver relevant search terms. “That’s an amazing piece of technology,” he said, adding: “It would take us years to replicate.”