09/14/2025
Expert Testimony Under Fire: What IP Lawyers Can Learn from "TB Holding v. J&S Siding"
In a recent Daubert ruling out of the District of Idaho, both parties in 'TB Holding Company, LLC v. J&S Siding' saw their damages experts excluded—highlighting how courts are tightening the reins on valuation testimony in patent cases. The dispute involved simulated log-siding machinery patents, but the real drama unfolded around royalty modeling and expert qualifications.
J&S’s expert, a seasoned accountant, admitted he’d never valued a patent and didn’t understand “reasonable royalty” concepts. TB Holding’s expert applied the Georgia-Pacific factors but failed to explain how they supported his unusually high royalty rate and upfront fee.
The ruling also touched on licensing data transparency, scope of design patent damages, and sealing financial exhibits. Each issue offers a lesson for attorneys preparing valuation evidence in IP litigation.
💡 Key Takeaways for IP Lawyers:
- Expertise Must Be Domain-Specific:Courts want experts with direct experience in patent valuation—not just general financial credentials.
- Georgia-Pacific Needs Quantification: Simply listing the factors isn’t enough. Experts must show how each one affects the royalty rate.
- Licensing Data Must Be Defensible: Keep a clean record of licensing comparables and disclose them early. Discovery discipline matters.
- Design Patent Scope Must Be Precise: Don’t overreach by bundling ancillary products. Stick to the “article of manufacture.”
- Sealing Requires Specific Justification: Courts won’t seal financials without compelling, well-supported reasons. Redact strategically.
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This case is a reminder that Daubert challenges are evolving—and so must our approach to valuation in IP disputes. If you’re advising clients on damages or preparing expert testimony, it’s worth revisiting your frameworks for defensibility and clarity.
