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Federal Circuit Confirms Microsoft Word Metadata Can Independently Corroborate Inventor Testimony Of Conception
11/03/2026On October 19, 2026, the U.S. Court of Appeals for the Federal Circuit affirmed the Patent Trial and Appeal Board’s final written decision in Google LLC v. Valtrus Innovations Ltd., No. 2024-1945 (Fed. Cir. Oct. 19, 2026), which found that the petitioner failed to establish that claims 1–23 of U.S. Patent No. 6,728,704 were unpatentable. The Federal Circuit held that Microsoft Word metadata can independently corroborate an inventor’s testimony regarding conception. The Court also held that substantial evidence supported the Board’s finding that the inventors exercised reasonably continuous diligence during the roughly 11 business days before the patent application was filed.
The ’704 patent claims methods and computer-readable memory for merging search-result lists from multiple search engines. In its IPR petition, the petitioner asserted obviousness grounds based on U.S. Patent No. 6,711,569 (“Bushee”) in combination with one or more additional references. Bushee was filed on July 24, 2001, approximately five weeks before the application that issued as the ’704 patent was filed on August 27, 2001.
The patent owner argued that Bushee was not prior art under pre-AIA 35 U.S.C. § 102(e) because the inventors conceived of the claimed invention before Bushee’s filing date and exercised reasonably continuous diligence until they filed their application. The Board agreed, relying on a co-inventor’s declaration, the original invention-disclosure documents, the metadata associated with those documents, and expert testimony. The Board therefore concluded that the petitioner had not shown that the challenged claims were unpatentable.
Under pre-AIA § 102(e), a patent owner may antedate a prior-art reference by showing (1) conception before the reference’s filing date and (2) reasonably continuous diligence from just before that date until the patent application was filed. When conception is proven through an inventor’s testimony, the patent owner must offer evidence beyond the inventor’s own statements and documents to corroborate that testimony. Corroboration is evaluated under the “rule of reason,” which considers all pertinent evidence to determine whether the inventor’s account is credible.
On appeal, the petitioner first argued that the invention-disclosure documents and their metadata could not independently corroborate the co-inventor’s testimony because they were under his control. The Federal Circuit rejected that argument. Applying the rule of reason, the Court concluded that the metadata was independent of the inventor’s own statements and documents because Microsoft Word generated it automatically rather than being authored by the inventor. Because the metadata’s authorship and timestamp information were consistent with the conception date in the inventor’s declaration, the metadata independently corroborated his testimony.
The Federal Circuit distinguished automatically generated metadata from unwitnessed laboratory notebooks, emails, and drawings, which cannot by themselves corroborate an inventor’s testimony of conception. The Court also explained that corroboration does not necessarily require a human source. It therefore held that substantial evidence supported the Board’s finding that the disclosure documents and metadata separately corroborated the inventor’s testimony.
The petitioner next argued that the Board lacked substantial evidence that the inventors were diligent between August 8 and August 27, 2001, a period of roughly 11 business days. The Federal Circuit rejected that argument as well. The Court explained that a patent owner need only show reasonably continuous diligence, not activity on every day, so long as the record shows that the invention was not abandoned or unreasonably delayed. Here, one inventor was based in Ontario, Canada, and his August 8 signature had to be mailed to the law firm’s California offices. In addition, the patent owner’s expert testified that law firms typically take several weeks or more to draft and finalize a patent application.
This decision is a reminder that pre-AIA patent owners may remove a key reference by swearing behind it, particularly when the reference was filed shortly before the patent application. Because automatically generated metadata can independently corroborate an inventor’s testimony, challengers cannot assume that conception evidence drawn solely from the inventor’s own files will fail for lack of a corroborating witness.
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