Meta Prevails in Landmark Antitrust Suit

In 2020, the FTC sued Meta seeking to undo its 2012 and 2014 acquisitions of Instagram and WhatsApp and to break apart the company, claiming that Meta was a monopolist in a market for “personal social networking” (PSN) and that it had “preserved its monopoly not by outcompeting its upstart rivals Instagram and WhatsApp, but by buying them.” Meta and its counsel, Kellogg, Hansen, Todd, Fiegel & Frederick, retained Compass Lexecon to act as consultants and experts in the case. Over the course of the roughly five-year litigation, six Compass Lexecon experts filed reports and testified at depositions: Professors Dennis W. Carlton, Daniel R. Fischel, Anindya Ghose, Steven Kaplan, John A. List, and Itamar Simonson.

The trial took place in the spring of 2025 before Judge James Boasberg of the US District Court of the District of Columbia and ran for more than six weeks. All six experts stood ready to testify at trial, but Meta ultimately shortened its rebuttal case to a single week, calling only Professors Carlton and List. Professor Carlton provided theoretical and empirical responses to the FTC’s primary economic expert’s wide range of claims. As part of those responses, Professor Carlton provided empirical analyses of natural experiments on a Meta outage and a TikTok shutdown. Professor List testified about market definition based on a field experiment that he created and ran, a natural experiment on a ban of TikTok in India, analysis of observational data from a Meta study panel, and a de-merger simulation accounting for the nature of the two-sided market.

On November 18, 2025, the Court released its opinion finding that “Meta holds no monopoly in the relevant market” and entered judgment in Meta’s favor. In reaching that conclusion, Judge Boasberg relied heavily on the testimony of “Meta’s experts List and Dennis Carlton.” The opinion notes that “much of the evidence discussed” comes from them. The experts’ live testimony is cited dozens of times in the opinion, which also reproduces multiple exhibits from their testimony.

In addressing market definition, the Court rejected the FTC’s claim that the only relevant competitors to Meta in the PSN market were Snap and MeWe. The opinion in particular points to the power of the groundbreaking field experiment by Professor John List, a pioneer in the use of experimental methods in economics. The experiment is the first major field experiment of its kind used in litigation. Professor List’s experiment included roughly 6,000 participants and evaluated how financial incentives to reduce Facebook or Instagram usage induced participants to reallocate their time to other apps and activities. This allowed Professor List to “test which apps they considered the next-best thing” to Facebook and Instagram.” Professor List’s field experiment methodology and results were accepted in their entirety by the Court.

Judge Boasberg’s opinion states that Professor List’s experiment “offers the single best evidence of what consumers consider alternatives to Meta’s apps, [and] tells a clear and consistent story: when using Facebook and Instagram becomes more costly, users turn to TikTok, YouTube, and Snapchat, with no other app notably standing out.” These results contradicted the FTC’s claim that TikTok and YouTube were outside the relevant economic market. The recognition of the usefulness of field experiments, an area in which Professor List is a pioneer, is an important development in antitrust litigation.

Judge Boasberg also favorably cited Professor List’s analyses of the natural experiment consisting of the ban of TikTok in India and of the observational evidence that analyzed how a study panel of 50,000 Meta users reallocated time when they changed their use of Facebook or Instagram. For the India analysis, Professor List used a “synthetic control—a weighted average of several countries constructed to match the pre-ban pattern of usage in India.” Judge Boasberg included in his opinion two trial exhibits from Professor List on the India natural experiment, finding that “[t]he results [in the figures] practically speak for themselves” that “TikTok takes an enormous amount of time away from Facebook and Instagram.” Similarly, Judge Boasberg pointed to Professor List’s conclusion that when members of the Meta study panel “cut time from Facebook and Instagram, they were most likely to devote it to YouTube and TikTok.”

Judge Boasberg also relied on Professor Carlton’s empirical analyses of two additional natural experiments, a 2021 Meta outage and a 2025 shutdown of TikTok in the US, noting that the analysis “reinforces that [TikTok and YouTube] are the closest alternatives to Facebook and Instagram…” Judge Boasberg concluded that it “is clear that the FTC’s hypothesis about how people use these apps is consistently disproven by the data.”

The six Compass Lexecon experts were supported by over one hundred staff, with Allan Shampine as the overall case manager and joint team lead for Professor Carlton with Mary Coleman, Hal Sider, and Niall MacMenamin as team leads for Professor List, Todd Kendall as team lead for Professor Ghose and joint team lead with Avisheh Mohsenin for Professor Kaplan, Quinn Johnson and Jessica Mandelas team leads for Professor Fischel, and Niall MacMenamin as team lead for Professor Simonson.

Compass Lexecon worked closely with Meta’s outside counsel, Kellogg, Hansen, Todd, Figel & Frederick, including Mark Hansen, Aaron Panner, Alex Parkinson, Evan Leo, Ana Paul, Ariela Migdal, Kevin Miller, Daniel Dorris, and Lillian Smith; and with counsel at Meta, including Scott Tucker, Christen Dubois, Eric Meiring, Arif Dhilla, and Nate Hopkins.