Trial Update, September 30, 2025: Google doesn’t use its First-Party Data to target open-web display ads?
September 30, 2025
Day 7 of US v. Google adtech remedies trial was as jam-packed as it was frustrating. We also got a sneak peek at the rest of Google’s case in chief. They will be calling three experts tomorrow, and a “small business” - presumably one of their late addition publishers. On Thursday, they will call one more Google witness, before resting their case in chief. This means that at least 8 out of Google’s 9 witnesses are or have been paid by Google. Maybe this explains why several Google witnesses have mind-bogglingly maintained that Google doesn’t use Google First-Party Data to target ads on open-web display. Alas, I digress.
Glenn Berntson, Director of Engineering @ Google
We resume with Berntson’s cross-examination. DOJ asks if Google would let publishers audit the final auction logic, and when Berntson dodges the question, Judge Brinkema pushes, saying that she is “interested in the answer” as the more information she has, the better decision she can make as to remedies. He says that he can’t speak for Google, but knowing how the systems work, providing more information to publishers “seems like a good idea.” Judge Brinkema asks him to clarify if his answer is “yes.” She reiterates that the government wants to know if Google would let publishers see how the final logic works. Berntson concedes a bit, saying that technical documentation or features to provide greater insight to publishers seems like a good idea, but the details of how this would work would need to be discussed.
Berntson says that the open sourcing of the auction logic is not the issue. The DfP remainder being separate, he says, doesn’t make sense because the calculation of EDA is problematic given the volume of data that needs processing, with the logic in one place and the data in another. This back-and-forth continues for a bit, and DOJ begins to unpack Berntson’s understanding of the Final Auction Logic open sourcing remedy. Berntson says that it was not his understanding that Google could continue to integrate the open sourced Final Auction Logic - which is strange as the Plaintiff’s proposal is very clear on this. He then says that doesn’t resolve his issue because it still separates the logic from the data. DOJ plays along and asks about whether if Google “copy and pastes” the auction logic, but continues to use it as it is today, that solves his problem. Berntson evades the question, and becomes defensive, saying something to the effect of “you’re asking me to analyze in real-time something vaguely hand-wavy.” Berntson admits that if they take existing code and share it, it would mitigate these concerns. He later calls DOJ’s characterization of the same issue of bid distribution calculations and EDA “either disingenuous or doesn’t understand how the system works.” DOJ says, “ooookay,” which serves to emphasize the witness’ hostility.
Judge Brinkema poses an analogy. The logic is the recipe. DfP has the recipe, and quantities of flour and eggs. Is this like giving the recipe to 3rd parties, without ingredients? Berntson says that if the focus is on transparency, the recipe does that, but providing actual data is different. He also says that users of the recipe may need to build new systems. Non-Google publisher ad servers could use it directly or adapt it to their systems. He acknowledges that other publisher ad servers would have their own publisher customers’ data - or ingredients. DOJ probes whether all of this historical bid data that DfP has for EDA is a competitive advantage over smaller ad servers, and Berntson gives the classic “I wouldn’t categorize it that way.”
On redirect, he is asked a question about the effects of the AdX divestiture proposal, which he deems would be detrimental. Judge Brinkema points out that there are other ad exchanges that are functioning, and he saves face by saying that this is why he thinks an ad exchange acquirer would be the most competent. We end with some jazz hands around malware and other protections for users and publishers. It makes sense, as he was noticeably low thus far on what I presume to be his buzzword bingo quota.
Noam Wolf, Sr. Director of Engineering at Google
DOJ calls Noam Wolf, their penultimate witness. First, DOJ elicits an acknowledgement that Google has previously increased latency to allow DSPs to have time to respond to bid requests, where it benefits publishers. We then go through Google’s engineering best practices a bit. GAM is a “large code base.” Google’s best practice is to organize large code bases into individual components so that individual components can be modified or replaced without disrupting the whole system. GAM, Wolf confirms, has been designed to be modular, with abstractions between layers of code. We get a funny request from the Judge for a non-technical analogy. She says “let’s say I want an upside-down cake,” and he explains that if she goes to the bakery and asks for it, she doesn’t need to know how they make it, just that she’ll get the cake in return. This is how he describes APIs. DOJ asks if this is similar to a drive-up window where one would order food. The analogy Weissman used, and Berntson scoffed at, Wolf affirms is apt.
Wolf is enjoyable to watch - and Judge smiles at his quips a couple of times which seem rooted mostly in academic precision than in arrogance or evasion. Asked if there is anything he didn’t like about the slides containing Google’s internal analysis of AdX divestiture and auction logic open sourcing, he said he didn’t like that the arrow for 2 years is one-third of the length of the arrow for 4 years, for example. He says that his team contributed to open source initiatives including prebid and IAB Tech Lab projects. He says that he was involved in the DfP AdX integration in 2014, where they modified existing code, wrote some new code, and still met service-level obligations, without disrupting DfP operation. We learn that Project Cerulean is the code name for the project about moving AdX to Google Cloud. His testimony ends without cross-examination by Google.
Nirmal Jayaram, Sr. Director of Engineering @ Google
Google calls their next Googler, Nirmal Jayaram. We heard from him during liabilities phase as well, where he frequently “wouldn’t characterize it that way.” I will preface this by saying that this testimony was incredibly frustrating to watch. He worked, until recently, on buy-side products, and begins with a well-scripted accounting of the negative impacts to advertisers of AdX divestiture, hitting all of the buzzwords he was ostensibly told to, like a good boy:
(1) User data signal loss
(2) Latency increase for ad loading
(3) Innovation suffers
(4) Reporting discrepancies, hindering billing
(5) Spam and Fraud
All amounting to a decrease in advertiser ROI. Judge Brinkema asks of the user data comes from other Google products like Search and he says, “No. It’s contained within Google ads,” going on to refer to cookies and explain that match rate on 3rd party exchanges is 90% - apparently as opposed to Google’s implicitly perfect match rate. He’s asked if the cookies “come from Google” and he says, “No, it comes from the browser.” Bummer that nobody asked him what browser most people used. He speaks to the chart showing that more Google Ads spend is flowing to YouTube, which is growing at a sharp rate as opposed to open-web display. As an aside, it is a pity that DOJ did not ask him about Pmax here, which many of Google Ads’ ~4 million small business users are nudged into by default, and gives Google the ability to route spending as they choose under the guise of optimizing performance for advertisers.
On cross-examination, DOJ beautifully points out that if divesting AdX reduces ROI - and thus quality - for the buy-side, that this implies that advertiser customers get lower value when bidding through 3rd party exchanges, as DV360 does already. Clearly, these concerns don’t stop DV360 from bidding through 3rd party exchanges. Jayaram also acknowledges that Google hasn’t done any analysis on these alleged deteriorations to their buy-side products. Further, on behavioral remedies, DOJ puts Jayaram in a corner. If Google doesn’t treat sell-side tools differently based on who owns them, then there’s no problem, as long as Google can make changes based on advertiser value, right? The same goes the other non-discrimination provisions. Jayaram reluctantly confirms.
Jayaram is asked if Google’s buy-side tools use Google First-Party Data for targeting users on open-web display. Like Craycroft, he says “no.” I am so, very confused at the mental gymnastics and word-play underpinning this wild misdirection. It is truly unclear to me how Google is not either misleading the court with this response, or misleading their advertiser customers; but, stay tuned because I intend to find out.
Rajeev Goel, CEO at Pubmatic
Goel’s direct was clearly intended to emphasize a few tight points. He explains that it is difficult to say to what extent the slower growth rate of open-web display is due to broader market dynamics, as Google has tried to argue, versus due to Google’s sell-side monopoly, and buy-side significant market share. He explains an interoperability issue that Pubmatic has been facing with Google for the past 8 months that remains unresolved, where a publisher can monetize with AdX, but not with Pubmatic. He also explains the measures Pubmatic takes to protect users from malware, to maintain security of its exchange, and privacy of user data. He says that AdX divestiture doesn’t create security concerns, as many others operate in the ecosystem without major security issues.
He describes the critical importance of scale to Pubmatic’s growth - scale of the platform, of volume of money and impressions flowing through it, of global relevance, and of ad formats the exchange supports. He discusses that investments in innovations are tied to the company’s scale as capital expenditure comes predominantly from profit reinvestment. Innovations include improving quality - like malware, security, and spam protection, as well as innovative uses of data to help publishers monetize better, in tech infrastructure, as well as support for other ad formats like native, digital out-of-home, and AI chat. He spoke to the way Pubmatic has invested in traffic shaping, as an example, to better determine which subset of ad impressions to send to a DSP, since none will take all 1 trillion ad impressions.
He explains that Pubmatic is on private cloud infrastructure, and that it has migrated from private to public cloud, and from public cloud to private. Moving from private to public has been done 4-8 times, as recently as a year and a half ago. It took 3-6 months to replace or remove dependencies. He explains that Pubmatic has used AI to help code when migrating to a new user-interface, automating 60% of the code writing. It went from a project that would have taken thousands of hours, to being completed in under two months with the help of AI. Similarly, building Header Bidding APIs takes a couple of weeks to a couple of months.
Dunn’s cross-examination was very aggressive and very long. She highlighted Pubmatic’s 10-K and shareholder statements where Goel spoke to a significant portion of Google’s 60% market share being up for grabs in 2026, prior to remedies proposals being filed. She wanted to get Goel to admit that he thought this was the case even without an assumption of structural remedies, but he explained he had no assumption of specific remedies, and Judge Brinkema moved things along.
Dunn digs into his statements about AI, attempting to elicit a concession that AI is moving users and thus dollars away from open-web display; but Goel provided examples to the contrary and explained that new monetization surfaces would include open-web display. She did get him to acknowledge that Pubmatic does have Programmatic Guaranteed deals, whereas we’ve previously heard testimony that GAM restricts this deal type to AdX. Dunn asks about a revenue shortfall disclosed in Pubmatic’s filings. She insinuates that it was due to running “dirty” 2nd price auctions - and I missed part of this, but it seemed to me the implication was that Google was the demand partner causing the shortfall, e.g. if Pubmatic ran afoul of UPR 1st price auction requirements. Nevertheless, she went on to highlight that these 2nd price auctions follow a 2018 Pubmatic announcement about moving to 1st price. Goel notes that the market has evolved, and their auction types are correctly declared.
Given Judge Brinkema’s question last week about the extent to which the preference for structural remedies by market participants is driven by a lack of trust in Google, Dunn asks Goel if this is the case, and he says it is an issue of incentives. On redirect, he is asked to expand on this, prompting Judge Brinkema to ask if this isn’t applicable to any business in a capitalist society. Goel explains that it is, and that’s why given Google’s dominant position on the sell-side, and significant position on the buy-side, it is to be expected that Google would use that to advance its shareholders’ interests. Judge Brinkema says that this gets at the elephant in the room - that Google is operating in a new environment. A court order would mean Google could be held in contempt, and Google is facing a number of lawsuits, including Pubmatic’s own, which Dunn had pointed out. “What are the impacts of those two swords of Damocles,” Judge Brinkema poses. Goel says that on the first “sword,” this is why the contents of the court order is so important. On the lawsuits, he says he doesn’t have an opinion - it is something Google will need to deal with.
What’s to come?
Tomorrow, we’ll hear from Google’s three experts and presumably a “small business” publisher. Thursday, Google will call Heather Adkins, VP of Security Engineering @ Google. Then, it’s rebuttal time. It is looking like the case will wrap either by the end of Thursday or on Friday.
I’ll be speaking at Capitol Forum’s 2025 Tech Conference, so there won’t be a newsletter. Here are some other folks doing great coverage:
