A clean USPTO assignment search can miss a transfer recorded months earlier.
In a recent opinion piece, Intellectual Asset Management (IAM) deputy editor Angela Morris alleges the public patent assignment data of the United States Patent and Trademark Office (USPTO) has been unreliable for years. Allied Security Trust (AST) reviewed 541,279 assignment documents with USPTO record dates from January 2024 through September 2026 and found that 70% did not appear in USPTO public assignment data until two or more calendar months after the record date. The median lag time among the delayed documents was about seven months. More than 66,000 of the delayed documents took more than a year to appear.
Data Disruptions and Delayed Records
The delays predate a two-month disruption of the USPTO’s patent assignment bulk data feed that IAM reports began in February 2026. AST reports that in the second half of 2025, between 12,000 and 40,000 previously delayed records surfaced in USPTO data each month. After the feed was restored, Richardson Oliver Insights (ROI) identified more than 1.4 million assignment records previously missing from the public dataset, including about 450,000 ownership-transfer records on non-provisional patent assets.
According to IAM, quarterly market reports, market indices, and transaction diligence built on USPTO assignment data now carry reliability warnings. IAM also reports that after nearly four months of waiting on its Freedom of Information Act (FOIA) request, the USPTO's FOIA officer responded that the office had no responsive documents.
Legal Ramifications Under 35 U.S.C. § 261
The legal consequences follow from the recording statute, 35 U.S.C. § 261. The statute directs the USPTO to maintain a register of interests in patents. An assignment not recorded within three months of its date, or before a later purchase or mortgage, is void against a later purchaser or lender who paid value without notice. Section 261 ties that protection to the date of recording at the USPTO, not to the date the record appears in public data. A diligence search during the lag can therefore miss an earlier, timely recorded assignment.
Diligence Steps That Account for the Delay
- Check the seller's executed assignments and USPTO record dates, in addition to public assignment data.
- Record new assignments promptly, since § 261 measures protection from the recording date.
- Treat transaction trends drawn from USPTO assignment data since 2024 as subject to revision as delayed records surface.
Until public USPTO data catches up with official record dates, the gap between recording and public visibility remains a concern for patent ownership diligence.
Sources
- IAM, "The USPTO must explain why patent assignment data is broken" (Oct. 10, 2026): https://www.iam-media.com/article/the-uspto-must-explain-why-patent-assignment-data-broken
- 35 U.S.C. § 261 (ownership; assignment): https://www.law.cornell.edu/uscode/text/35/261