By Atreya Mathur
In 2020, Thomson Reuters, owner of the widely used legal research platform Westlaw, filed suit against ROSS Intelligence Inc., a start-up developing an AI-driven legal research tool. The dispute centers on Westlaw’s “Headnotes,”editorial summaries and points of law that precede judicial opinions on the platform.[1] In their complaint, Thomson Reuters alleged that ROSS copied thousands of these headnotes to train and populate its competing system, rather than independently creating its own summaries, and did so without authorization.[2] The complaint alleged copyright infringement and tortious interference, and included claims that ROSS misappropriated proprietary data by using Westlaw headnotes without authorization.[3] ROSS denied liability, arguing that its use of the headnotes was protected under fair use and necessary for innovation in legal technology.[4]
Importantly, this case involves a non-generative AI system. According to Thomson Reuters and the district court’s findings, ROSS obtained and used copyrighted Westlaw headnotes in developing its legal-research tool.[5] Unlike generative AI platforms, which are designed to produce new content such as text, images, or music from learned patterns, ROSS’s system was built to organize and deliver legal information for research purposes rather than to generate new expressive works.[6] This distinction matters because the court’s analysis focused on whether ROSS’s use functioned as a substitute for Westlaw’s editorial content and harmed its market, rather than on whether AI training alone constitutes transformation or creative output.[7]
In February 2025, the United States District Court for the District of Delaware issued a significant ruling on cross-motions for renewed summary judgment. The court held that ROSS had infringed the copyright in thousands of Westlaw headnotes and that its fair use defense failed as a matter of law for a large subset of the works.[8] The court emphasized the commercial nature of ROSS’s conduct, the lack of meaningful transformation, and the realistic risk of market substitution.[9] On March 18, 2025, ROSS Intelligence filed its Opening Brief in support of its Motion for Interlocutory Appeal and Stay Pending Appeal. ROSS contends that the district court erred in its summary judgment ruling, arguing that the Westlaw headnotes are not copyrightable and that its use of them constitutes fair use.[10] On April 1, 2025, Thomson Reuters filed its Opposition to ROSS's Motion for Interlocutory Appeal and Stay Pending Appeal. Thomson Reuters argues that the district court's decision was correct and that ROSS's use of the headnotes infringes upon its copyrights.[11] On May 23, 2025, the district court granted ROSS's motion for interlocutory appeal and stay pending appeal, certifying two questions for the Third Circuit: (1) whether the Westlaw headnotes and Key Number System are original, and (2) whether ROSS's use of the headnotes was fair use. The court noted that these issues present substantial grounds for a difference of opinion and have the potential to materially advance the litigation.[12] On September 22, 2025, ROSS filed its Opening Brief in the Third Circuit, challenging the district court's rulings on copyrightability and fair use. ROSS argues that the headnotes are not copyrightable and that its use of them was transformative and non-infringing.[13]
Dear Visitor,
We share your curiosity for art law. Thank you for reading our complimentary articles for the month. To read more free articles, please register for a free account. For even more access and perks, consider becoming a premium member!Already a premium member? Sign in
Or, become a premium member for unlimited access