Patent lost-profits damages expert
Expert class library · Intellectual property · Plaintiff side
Calculates the sales and profits a patent owner lost because of infringing competition, including diverted sales and price erosion. Applies the Panduit factors or a market-share approach, and must account for acceptable non-infringing alternatives to show but-for causation.
What this expert is retained to answer
- Was there demand for the patented product and an absence of acceptable non-infringing alternatives?
- If alternatives existed, what share of the infringer's sales would the patentee have captured under a market-share approach?
- Did the patentee have the manufacturing and marketing capacity to make the diverted sales?
- Would the patentee have charged higher prices but for the infringement?
- What incremental profit would the patentee have earned on the lost sales?
Methods
- Panduit factor analysis
- Market share approach
- Price erosion analysis
- Incremental profit calculation
How the testimony is attacked
- Ignoring non-infringing alternatives. Defendants argue the expert never addressed acceptable substitutes and so cannot show but-for causation. In Syngenta v. Willowood the court excluded the lost profits opinions on two patents because the expert did not address how alternatives affected those damages.
- Unreliable benchmarks or budget projections. Opponents attack the benchmarks used to build the but-for world. The Syngenta court found that adjusting one benchmark with another can be reliable when the benchmarks are appropriate, and admitted the analysis for the compound patents.
- Market share approach used to dodge Panduit's second factor. Defendants argue the patentee cannot get lost profits where competitors offer substitutes. In Sonos v. D&M the court held the market-share approach is a recognized substitute for proving absence of alternatives and denied the motion to strike.
- Unsupported assumptions about alternatives and price. Challengers fault the expert for assuming no acceptable alternatives or price effects without support. In Dorman v. Paccar the court held a damages expert may quantify lost profits and price erosion on assumptions that other trial evidence must prove.
- Customer-by-customer analysis. Defendants argue entitlement must be shown sale by sale. The Sonos court acknowledged the customer-specific inquiry but held that whether alternatives were commercially acceptable was a question for the jury.
What the public record shows
A deliberately narrow CourtListener search, Panduit AND "lost profits" AND patent AND (Daubert OR "Rule 702"), returned 8 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 |
|---|---|---|---|
| Limited | Syngenta Crop Protection, LLC v. Willowood Azoxystrobin, LLC267 F. Supp. 3d 649 | M.D.N.C. 2017 | The court admitted the patentee's benchmark-based lost profits calculation for two patents but excluded it for two others because the expert failed to account for non-infringing alternatives and so did not show but-for causation. |
| Admitted | Sonos, Inc. v. D&M Holdings Inc.297 F. Supp. 3d 501 | D. Del. 2017 | The court denied the motion to strike the patentee's lost profits analysis because the expert used the accepted market-share approach in a multi-competitor market, while excluding his separate reasonable royalty opinion for failure to apportion. |
| Admitted | Dorman Products, Inc. v. Paccar, Inc.201 F. Supp. 3d 663 | E.D. Pa. 2016 | The court denied the Daubert motion against the patentee's damages expert because he offered lost profits and price erosion figures only to quantify damages, not to prove the absence of alternatives, which other trial evidence would have to establish. |
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.
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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.