Exclusionary-conduct damages economist
Expert class library · Antitrust · Plaintiff side
Builds a but-for world without the alleged exclusionary conduct to measure the profits a foreclosed rival lost or the overcharges buyers paid. The model must rest on reliable projections and must separate harm caused by the unlawful conduct from harm caused by lawful competition.
What this expert is retained to answer
- What market share and profits would the plaintiff have earned absent the exclusive dealing, tying, or other exclusionary conduct?
- Are the business projections underlying the but-for world reliable and independently verified?
- Does the damages model separate losses caused by the challenged conduct from losses caused by lawful conduct such as a permissible refusal to deal?
- How much of the market did the challenged contracts foreclose?
Methods
- But-for market share modeling
- Yardstick and benchmark analysis
- Disaggregation of lawful and unlawful conduct
- Lost profits from foreclosure
How the testimony is attacked
- Reliance on unverified business projections. Defendants argue the but-for world rests on management forecasts the expert did not test. In ZF Meritor v. Eaton the Third Circuit affirmed exclusion of damages built on a one-page business plan whose authors, methods, and assumptions the expert did not know.
- Failure to disaggregate lawful conduct. Opponents show that the model attributes all losses to conduct that includes lawful acts. In Viamedia v. Comcast the district court excluded the damages expert because his entire estimate flowed from the plaintiff's loss of access to the interconnects, which the court treated as a lawful refusal to deal.
- Gerrymandered foreclosure calculation. Defendants claim the expert dropped large buyers or channels to inflate foreclosure shares. In Insight Equity v. Transitions Optical the court allowed the expert to rely on an industry list of top retailers and largely rejected this attack.
- Projections distinguished from ZF Meritor. Plaintiffs answer reliance attacks by showing the projections were detailed and prepared for business purposes such as lending. The Insight Equity court distinguished ZF Meritor on that basis and admitted the damages implementation.
- Contradiction by other record evidence. Defendants argue the model ignores contrary facts. The Third Circuit agreed that conflicting evidence alone is not grounds for exclusion and that the experts' relative credibility was for the jury, while still upholding exclusion on the separate projections problem.
What the public record shows
A deliberately narrow CourtListener search, monopolization AND "but-for" AND damages AND disaggregat* AND (Daubert OR "Rule 702"), returned 1 opinions filed since 2015, as of October 2, 2026; broader searches return more. Three that show how courts handle this class of testimony:
| Outcome | Case | Court | Why |
|---|---|---|---|
| Excluded | ZF Meritor, LLC v. Eaton Corp.696 F.3d 254 | 3d Cir. 2012 | The Third Circuit affirmed exclusion of the plaintiffs' damages opinion under Rule 702 because the but-for profits came from a summary business plan whose origin and assumptions the expert could not explain, though it allowed the plaintiffs to submit alternate calculations. |
| Exclusion reversed | Viamedia, Inc. v. Comcast Corp.No. 18-2852 | 7th Cir. 2020 | The Seventh Circuit reversed the district court's exclusion of the plaintiff's damages expert, which had rested largely on the view that the refusal-to-deal claim failed as a matter of law, a view the appeals court rejected. |
| Admitted | Insight Equity v. Transitions Optical, Inc.252 F. Supp. 3d 382 | D. Del. 2017 | The court largely admitted the plaintiff's foreclosure and but-for damages testimony in an exclusive dealing case, and admitted the damages implementation in full because it relied on detailed company projections unlike the thin plan in ZF Meritor. |
Each case links to the free opinion text on CourtListener.
Under amended Rule 702
Since December 1, 2023, Rule 702 says expressly that the party offering an expert must show the court it is more likely than not that the testimony meets each requirement: that it rests on sufficient facts or data, uses reliable methods, and reflects a reliable application of those methods to the case. Questions about the basis of an opinion are no longer automatically matters of weight for the jury. For how the circuits have applied the amendment, see the Rule 702 tracker, which follows each court of appeals; for what that means for preparing or attacking this class of expert, see the guide on amended Rule 702.
Related classes
Guides
- Common Impact and Pass-Through at Class Certification
- Amended Rule 702 After Nearly Three Years: What Courts Exclude
Simulating this class on a matter
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Last reviewed October 2, 2026. How this page is built: rulings are found by searching court opinions on CourtListener, and each one is read in the opinion before it is summarised here; outcomes are labelled by what the court did with the expert's testimony. No individual expert is named. This page summarises public decisions for orientation and is not legal advice; read the opinion before relying on any ruling.