Who Will Win the Tug-of-War Between Europe and Big Tech?

After a final hearing on November 4, 2025, Italy’s competition authority (AGCM) issued what is already a landmark decision in the European debate on privacy and competition: on December 22, 2025, it announced a €98.6 million fine against Apple entities. The authority argues that Apple’s App Tracking Transparency (ATT) framework, as implemented, imposed a “double consent” burden that disadvantaged third-party developers and advertisers. Apple has said it will appeal. Ironically, Apple secured an interim ruling in its favor in France just weeks later. On January 20, 2026, the president of the Paris Judicial Court rejected an emergency request from advertising-industry groups to suspend ATT, allowing the framework to remain in place while the broader disputes continue. The coalitions behind the request have said they are examining appeal options. Unsurprisingly, the plaintiffs confirmed that they will pursue legal action against ATT.

A Citation that Matters, and a Critique that Changes the Story

The AGCM decision includes a reference to academic research on how tracking restrictions can affect advertising revenues, cosigned by three academics from HEC Paris and Goethe University Frankfurt. The Italian authorities say their research “demonstrate(s) that in the absence of customization possibilities, such revenues decrease, estimating this negative impact at around 18-23%.” 

The researcher cited, Professor Klaus M. Miller of the Marketing Department at HEC Paris, welcomes that visibility. But he says the way research is used in legal documents often stops too early at a headline figure, instead of informing the harder question regulators ultimately face. 

“It’s positive that competition authorities are citing academic research, many don’t. That said, our paper appears in a background section establishing that ‘data matters for advertising,’ which isn’t the contested question. The proportionality analysis would require asking how much harm and to whom and our paper actually addresses this: we find premium and niche publishers suffer less, and that simple user identifiers generate most of the value while intrusive browsing history adds little for publishers.”

Miller’s point is not that authorities should abandon privacy goals. It is that proportionality cannot be evaluated from averages alone. To do proportionality well, he says, authorities have to specify who bears the costs and which elements of data collection actually drive economic value. And the HEC Paris researcher shares abundant advice in the ongoing scrutiny of Apple’s policies in implementing ATT directives.

What Miller’s paper shows, in the authors’ own terms

The paper Miller co-authored with Doctor René Laub and Professor Bernd Skiera (both Goethe University Frankfurt) is titled “The Economic Value of User Tracking for Publishers.” Across two large-scale empirical studies, the authors estimate that when user tracking is unavailable, ad impression prices decline on average in the EU. 

“In our first study, we draw on 42 million ad impressions from 111 publishers covering EU desktop browsing traffic,” explains Miller. “In our second study, we use 218 million ad impressions from 10,526 publishers (i.e., apps) covering EU and US mobile in-app browsing traffic in 2023.” 

The three researchers also report meaningful variation across publisher types, and they distinguish the value of basic identifiers from more intrusive data. “The AGCM correctly cites our main finding: tracking restrictions reduce ad revenues by around 18-23%, “says Miller. “What’s underexplored is the heterogeneity beneath that headline: which publishers suffer most, and which data types actually matter.” He continues: “The risk in translating academic findings into policy is treating an average effect as uniform and treating the cost side of a trade-off as the whole picture. Our paper quantifies costs; it doesn’t say whether those costs justify the privacy benefits users receive.”

Why “how much, and to whom” is the key question for enforcement

For Miller, the contribution of the research is not simply to show that tracking restrictions have costs. It is to show that these costs are not evenly distributed, and that data categories differ in both economic value and perceived intrusiveness. 

That, in turn, can help regulators structure proportionality analysis and remedies. “Based on our research, general news sites and larger publishers suffer most; niche and premium publishers are more resilient, likely because their context already signals user intent. And interestingly, simply knowing who the user is generates most of the value; detailed browsing history adds little for publishers. That’s policy-relevant: the most privacy-invasive data isn’t necessarily the most economically valuable.” 

Miller underlines that his research shows that not all tracking is equally valuable and not all tracking is equally invasive: “The policy implication is that well-designed regulation could restrict the most intrusive practices while preserving most of the economic value.”

The academic argues that the next rounds of enforcement can be – and arguably should be - more evidence-led. France, he notes, has already shaped how the issue is framed. On March 31, 2025, France’s Autorité de la concurrence fined Apple for practices linked to ATT and notes that the decision is under appeal. “France’s framing has influenced how subsequent authorities approach the issue.”

What solution-based enforcement could look like

In Germany, meanwhile, the independent competition authority, Bundeskartellamt, announced on February 13, 2025 that it had sent Apple its preliminary legal assessment on the App Tracking Transparency Framework (ATTF). “I hope regulators move beyond citing research for background and actually use it to calibrate their analysis,” notes Miller. “Our findings on heterogeneity could sharpen the proportionality question: who exactly is harmed and by how much. Our findings on data types could inform remedy design. The research exists to help quantify trade-offs, not just to establish that trade-offs exist.”

Miller emphasizes that privacy benefits are real, too. Enforcement, he says, should focus on practical fixes rather than symbolic confrontation. His recommendations focus on design choices that can preserve user control while reducing competitive distortion. “Fines are signals, not solutions. I’d prioritize design remedies: one-step consent, symmetric treatment of Apple’s ads, and equal measurement access. Then audit to ensure it’s working. And ideally, regulatory sandboxes could catch these issues upstream, letting platforms test privacy frameworks with regulator input before they become competition cases.”

Future cases coming up in France and Germany

However, the academic does not underestimate the challenges posed to legislation: “The privacy benefits to users are real: ATT gave people a choice they didn’t have before. But the competitive effects are also real, and the implementation choices may have favored Apple.” Apple maintains that its first-party apps do not engage in cross-app tracking and therefore do not require the same consent flow, a position that any proportionality assessment would need to examine on its merits.

With future cases looming in 2026, one issue appears self-evident: authorities can lean on research which does more than support a narrative. It can help regulators specify which groups are harmed, how large the harm is, and how remedies can target the most invasive practices without unnecessarily stripping value from the broader ecosystem.