The first federal appeals ruling on ai training just landed against fair use. the third circuit…
the first federal appeals ruling on ai training just landed against fair use. the third circuit held on sept 29 that ross's use of westlaw headnotes to train its legal research tool was infringement, in thomson reuters v ross intelligence.
one appellate court has now set the floor for what training on copyrighted work means.
Context
Courthouse News reported on September 30, 2026 that the Third Circuit rejected ROSS Intelligence's fair use defense and affirmed a lower court ruling that ROSS infringed Thomson Reuters' Westlaw headnotes by using them to train its AI legal research product. It says Judge Tamika Montgomery-Reeves wrote for the panel, that the headnotes showed enough creative spark to be protected, and that ROSS's use harmed the market for Westlaw and the potential market for licensing headnotes to train AI.
The report says the lower court had found ROSS's use insufficiently transformative and that ROSS used the data to build a competing product, not for legal research. The opinion, No. 25-2153, is listed with a filing date of September 30, 2026.
The Third Circuit's rejection of fair use for ROSS's training matches the report. The note gives the ruling date as September 29. The opinion document read shows a filing date of September 30, 2026, and a Leagle listing is dated September 29, so the exact decision date is not settled by the pages read.
The note calls this the first federal appeals ruling on AI training. The pages read call it potentially a landmark precedent and do not say it is the first appellate ruling, so 'first' is unsupported here, not refuted.
The reasoning in the report is tied to a competing legal research product and to headnotes with a creative spark. 'Set the floor for what training on copyrighted work means' is the author's reading, and the report does not say how far the holding reaches to other kinds of AI training.
Related work
- AI training of copyrighted material not fair use: Third Circuit (Courthouse News Service, September 30, 2026) ↗Primary news source for the holding, the judge, the reasoning and the history.
- Thomson Reuters Enterprise Centre GmbH v. Ross Intelligence Inc., No. 25-2153 (3d Cir., opinion filed September 30, 2026) ↗The opinion document, with its filing date.
Watch next
- Read the opinion's discussion of the type of AI at issue. Look for how other circuits are handling pending AI training cases.
Sources
Provenance
The note above is reproduced unedited from the original post, first published on Threads on 9 October 2026 at 03:56 IST. Sources are the papers and datasets the note draws on.
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