The US DOJ and Google made their closing arguments in the ad-market antitrust case before Judge Leonie Brinkema, who expressed some skepticism toward both sides
Tech Giant Says 31% and Falling Lauren Feiner / The Verge : Google and the DOJ make their final arguments in the ad tech monopoly case Marty Swant / Digiday : DOJ and Google make closing arguments in landmark adtech antitrust trial New York Times : The ‘Rocket Docket’ Judge Who Will Decide the Fate of Google's Ad Technology Ezza Ijaz / Wccftech : Google And DOJ Deliver Closing Arguments In The Ad Tech Monopoly Case As The Legal Battle Reaches A Critical Juncture Kristijan Lucic / Android Headlines : The DOJ says Google is “once, twice, three times a monopolist” Hürriyet Daily News : US-Google face off as ad tech antitrust trial comes to close Matt G. Southern / Search Engine Journal : DOJ Says Google Controls 91% Of Ad Market; Google Says 10% Mudit Dube / NewsBytes : Google presents final arguments in ad tech monopoly case Erin Woo / The Information : DOJ, Google Make Closing Arguments in Second Google Monopoly Case PYMNTS.com : Google Faces DOJ's Final Arguments in Antitrust Showdown Over Ad Tech Alex Pigman / International Business Times : US-Google Face Off As Ad Tech Antitrust Trial Comes To Close David Cohen / Adweek : DOJ Presents Final Argument in Adtech Antitrust Suit vs. Google Matthew Barakat / Associated Press : Judge hears closing arguments on whether Google's advertising tech constitutes a monopoly Peter Kafka / Business Insider : Inside ‘Project Black Walnut’ that sheds light on how Google thinks about Apple's ad business Reuters : Google's US antitrust trial over online ad empire draws to a close X: Matt G. Southern / @mattgsouthern : The DOJ wraps up another case against Google. DOJ claims 90%+ market dominance; Google counters with 10%, citing competition from Meta & TikTok. The Judge's verdict, expected at year-end, could force Google to divest its ad tech business. [image] Lauren Feiner / @lauren_feiner : Google and DOJ made their final arguments to Judge Brinkema in the ad tech monopoly case. Now we await a decision, expected to come by the end of the year. If she rules for the DOJ, the parties could soon be engaged in double remedies trials https://www.theverge.com/... Jason Kint / @jason_kint : Lastly, maybe most powerfully, as Google lead counsel, Dunn, closed hard leaning multiple times on chart showing Google's ad growth outpaced by a much larger display ad market, Court called her on it and forced her to admit her chart also included CTV, social media and apps. /8 Jason Kint / @jason_kint : On deception, DOJ didn't bring up Google's evidence deletion or mislabeled docs. The Court did! She made clear she hadn't forgotten this and how other courts had ruled on it as G tried to leverage internal messages in defense. DOJ hammered it home again when they wrapped. /4 Jason Kint / @jason_kint : On complexity, Google again executed on its spaghetti defense with lead counsel, Karen Dunn, bookending trial by running over as she did in her opening. She appeared to skip dozens of slides, many minutes of close. And she loaded her slides while talking twice as fast as DOJ! /3 Jason Kint / @jason_kint : US v Google II Closing arguments today. 70min for DOJ-> 95min for Google-> 20min for DOJ. Having predicted this case as better odds than search case (Google already lost in August), nothing changed my mind today. I wrote down: influence/$, complexity, deception, and arrogance. /1 Jason Kint / @jason_kint : I'm staying high level on perception first as findings of fact already covered much. On influence/$, DOJ pointed out early on and then again in rebuttal that every single witness presented by Google (except one) was paid or had grants from Google. /2 See also Mediagazer
Context & Ripple Effects
The proceeding grew out of the DOJ-led lawsuit seeking a breakup of Google’s ad-tech business, and Google had already completed its trial defense before the final arguments. The dispute now turns on sharply different definitions of the market and Google’s place within it.
Brinkema’s skepticism of both sides leaves the central claims unresolved, but the case is a direct test of whether control across ad-tech functions can be treated as platform gatekeeper leverage rather than ordinary competition.
First-order effects
- The DOJ and Google have finished presenting their merits case; the next consequential step is Judge Brinkema’s ruling on whether Google unlawfully monopolized the relevant ad-tech markets.
- The parties’ immediate exposure remains tied to competing market-share theories: the DOJ argues Google’s control exceeds 90%, while Google cites a far smaller share and competition from Meta and TikTok.
Second-order effects
- A ruling for the DOJ would put Google’s ad-tech operations under heightened remedy scrutiny, consistent with the breakup request in the original DOJ and state complaint.
- Publishers, advertisers, and rival ad-tech firms will closely parse how the court defines the market, because that definition determines whether integrated ad-tech services are assessed together or against a broader set of digital-ad competitors.
Third-order effects
- If courts increasingly accept the DOJ’s framing, antitrust enforcement could focus more on control of interconnected digital-market infrastructure, not just a platform’s consumer-facing share.
- The case also illustrates a broader judicial test: whether large platforms can defend integration by pointing to adjacent competitors when regulators allege dominance at specific transaction layers.
The trend: Digital antitrust cases are increasingly contesting how markets are defined around the infrastructure layers that connect buyers, sellers, and data.