Federal Circuit: ITC Experts May Rely on Source Code Not Admitted at Hearing

On May 11, 2026, the US Court of Appeals for the Federal Circuit issued a precedential decision in Bissell, Inc. v. International Trade Commission, affirming the ITC’s final determination in Investigation No. 337-TA-1304, preventing respondent Tineco from importing its original wet/dry surface cleaning device but allowing the importation of its redesigned devices. Among other issues, the court held that an ITC expert may rely on source code produced in discovery even if the source code is never introduced as a hearing exhibit.

The decision underscores the latitude ALJs and the Federal Circuit afford expert testimony in software- and firmware-driven investigations, and the litigation risk of failing to meaningfully test an opposing expert’s technical analysis through cross-examination or competing expert evidence.

Background

Bissell, Inc. and Bissell Homecare, Inc. (collectively, “Bissell”) filed an ITC complaint alleging that Tineco Intelligent Technology Co., Ltd.; TEK (Hong Kong) Science & Technology Ltd.; and Tineco Intelligent, Inc. (collectively, “Tineco”) violated Section 337 of the Tariff Act by importing and selling wet/dry surface-cleaning devices that infringe certain claims of US Patent Nos. 11,076,735 and 11,071,428. The ITC found a violation as to certain accused products and entered relief barring importation of those infringing products. The ITC also determined that Tineco’s redesigned products did not infringe certain asserted claims, and therefore, no exclusion order issued as to the redesigned products.

Bissell appealed the finding of no violation for the redesigned products. Tineco cross-appealed, challenging (among other things) the ITC’s finding that Bissell satisfied the technical prong of the domestic industry requirement. The Federal Circuit affirmed the ITC’s final determination in full.

Tineco’s Cross‑Appeal on Domestic Industry

On cross-appeal, Tineco argued that Bissell failed to satisfy the technical prong of domestic industry, focusing on a limitation requiring a “disabled battery” condition during a self-cleaning cycle. Tineco contended that the ALJ should not have credited Bissell’s expert (Dr. Khalid Sorensen) because his opinion relied on Bissell source code that was produced in discovery but not admitted into evidence at the hearing.

The Federal Circuit rejected that argument.

The Federal Circuit’s Decision Affirms the Application of Federal Rule of Evidence 703 at the ITC

The court grounded its analysis in Federal Rule of Evidence 703, which permits an expert to base an opinion on facts or data that are not themselves admissible, so long as experts in the field would reasonably rely on those materials.

Quoting Rule 703, the court emphasized:

“An expert may base an opinion on facts or data in the case that the expert has been made aware of or personally observed.... If experts in the particular field would reasonably rely on those kinds of facts or data ... they need not be admissible for the opinion to be admitted.” Fed. R. Evid. 703.

On the record presented, the court found several points decisive:

• The source code was produced in discovery;
• Bissell’s expert reviewed the source code and relied on it in forming his opinion;
• Experts in the field reasonably rely on source code to understand device operation; and
• Tineco did not meaningfully rebut the testimony through cross-examination or competing expert evidence.

The Federal Circuit concluded that “[u]nder the circumstances presented in this case ... an expert can rely on source code without a party introducing that source code into the evidentiary record.” Bissell, Inc. v. Int’l Trade Comm’n, Nos. 2024-1509, 2024-1709, at 13.

Practical Significance: Experts May Rely on Inadmissible Materials — and Even Hearsay

Practically, the ruling is consistent with a familiar evidentiary principle: Experts may base opinions on materials that are not themselves admissible, provided that experts in the field would reasonably rely on those materials. In particular, the expert testimony of Dr. Sorensen relying on the unadmitted source code may constitute hearsay, but the ITC may “admit hearsay as substantive evidence if it is otherwise ‘relevant, material, and reliable.’” See Certain Photovoltaic Trunk Bus Cable Assemblies & Components Thereof, Inv. No. 337-TA-1438, Final ID at 58 (Feb. 6, 2026).

That principle is especially important in ITC investigations involving software or firmware, where:

• Source code is often voluminous, highly confidential, and difficult to present efficiently at hearing;
• ALJs often rely on expert explanation and synthesis of technical materials; and
• The accelerated schedule requires parties to prioritize technical clarity and persuasion.

The ITC’s evidentiary framework already affords ALJs substantial discretion in how to admit and weigh evidence. The Federal Circuit’s decision confirms that Rule 703 applies at the ITC when parties attempt to limit expert testimony based on whether underlying technical materials were admitted as exhibits.

The Reliance on Evidentiary Objections Alone May Not Excuse the Failure to Rebut Expert Testimony

Equally notable was what Tineco did not do. The Federal Circuit observed that Tineco:

• did not argue in its prehearing brief that the domestic industry products failed to meet the limitation;
• did not cross-examine Dr. Sorensen on his reliance on the source code; and
• offered no competing expert testimony on the issue.

Against that backdrop, the court treated Dr. Sorensen’s testimony as nonconclusory and unrebutted, and therefore sufficient to constitute substantial evidence.

The message for ITC litigants is straightforward: If an opposing expert relies on produced technical materials, a record focused only on admissibility objections — without effective cross-examination or counter-expert analysis — can be difficult to overcome on appeal.

Practical Takeaways for ITC Litigants

This decision offers several practical takeaways for parties litigating software-driven disputes at the ITC:

• Experts Have Broad Latitude: Experts may rely on discovery materials — including source code — without the materials being admitted as hearing exhibits.
• Rebuttal Matters More than Formal Objections: Substantive rebuttal (cross-examination, competing expert opinions, or both) is often more effective than objections focused solely on exhibit status.
• Strategic Consideration for Complainants: Even if admission is not required, parties may still choose to offer source code (or curated excerpts) where a limitation is sharply contested and a direct exhibit record would be useful.

Conclusion

The Federal Circuit’s decision in Bissell v. ITC reinforces the flexibility afforded to expert testimony at the ITC and confirms that experts may rely on source code produced in discovery even if it is not admitted into evidence at the hearing.

For parties litigating software-driven cases before the ITC, the opinion also highlights a record-building point: Testing expert opinions through cross-examination and competing technical evidence can be critical, particularly given the deferential substantial-evidence standard on appeal.

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