In early September, Google sidestepped a federal effort to break up the corporation when U.S. District Court Judge Amit Mehta rejected a Justice Department demand that Google spin off its Chrome browser as remedy for violating antitrust law. But in recent hearings on how to remedy Google’s monopolization of advertising technologies (adtech) — found to be illegal in a second antitrust case — the discussion appeared to point to a more severe outcome.

In the hearings, the DOJ and Google spent two weeks arguing before federal judge Leonie Brinkema about how best to undo Google’s monopoly over ad tech. The hearings, which concluded October 6, revealed a united front between technical experts, news publishers, and adtech providers, who unanimously argued that structural remedies are not merely feasible but necessary to resolve the problem.

Adtech platforms enable the automated buying and selling of online advertising, by connecting online publishers and advertisers. In April 2025, Judge Brinkema ruled that Google illegally monopolized this market to favor its own business, including by crushing competitors that offered better prices. The decision effectively found that Google has denied publishers much of their freedom to increase their ad revenues while also enabling Google to extract monopoly rents from them.

To end these practices for good, the DOJ asked the court to force Google to divest its ad exchange, AdX, which gathers bid requests from advertisers and runs millisecond-long auctions to match them with publishers. The DOJ is also asking for a partial divestiture of Google’s ad server, DoubleClick for Publishers (DFP), which handles 90% of global publishers’ ad inventory. The government’s plan would transform DFP into an open-source code for publishers and other ad tech platforms to use, effectively breaking Google’s sole control of the algorithms that determine the outcomes of ad auctions.

One key witness was Goranka Bjedov, a former Senior Performance Test Engineer at Google. She laid out timelines and technical steps to fulfill the DOJ’s proposal. Even as Google’s lawyers attempted to delegitimize Bjedov’s expertise, her analysis echoed Google’s own internal analysis (admitted as evidence but sealed to the public) that divesting or shutting down AdX and open-sourcing DFP are both technically feasible. Bjedov is currently a Capacity Engineer at Facebook — where she has worked in redesigning Facebook’s own adtech stack.

On the side of news publishers, the strongest testimony came from former News Corp. executive Stephanie Layser, now head of publisher adtech solutions at Amazon Web Services. Layser emphasized how the future of a viable press for the open web hinges on publishers and advertisers regaining control of the adtech platforms that represent them, which Google’s monopoly has prevented for over a decade.

Asked by Judge Brinkema about the need for structural separations, Layser warned against relying on behavioral remedies, which she said would only enable Google to create new ways to pursue undetectable anticompetitive practices. Google’s absolute control of the algorithms that decide why ads are sold at a certain price and access to all transaction records is what has made it so difficult to uncover the magnitude of its illegal behavior in the first place, Layser said. “We need publishers to validate [publisher server data] and need the industry to be able to innovate on top of that so we can move forward from this.” 

Witnesses from marketing and ad agencies, as well as rival adtech providers, agreed with Layser and Bjedov. Rajeev Goel, CEO at the ad tech company Pubmatic, attacked Google’s argument that the present structure of the industry is the result of a natural “market dynamic” rather than of Google’s monopoly power. Goel detailed how Google’s dominant position on all sides of this market prevents competitors from developing more transparent and effective products. Pubmatic recently sued Google for damages based on Brinkema’s liability ruling that Google had built an illegal monopoly.

Judge Brinkema will likely issue a ruling on the remedies in early 2026. Although it is impossible to predict what she will ultimately decide, the witnesses made a strong case for dramatic action. As Jed Dederick, Chief Revenue Officer at The Trade Desk, an ad server that has pivoted from open-web advertising to connected TV ads, put it, if the DOJ’s demands are not adopted, there will be a sense that Google “got away with it.”

The U.S. is not the only jurisdiction where Google is awaiting a decision to break up its adtech stack. In September, the European Commission fined Google $3.45 billion for abusing its dominance in this market, ordering it to end its illegal conduct in 60 days or otherwise have the Commission impose all necessary remedies to achieve that outcome, including a break-up of its adtech business.