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Thomson Reuters keeps its win over ROSS in the first appellate test of AI-training fair use

Thomson Reuters kept its copyright win over ROSS Intelligence on appeal, the first US appellate ruling on fair use in AI training. ROSS had been refused a Westlaw licence as a rival, so the ruling lets owners of training data set a price or decline to sell.

The Investor · Invest desk

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What happened

  • Judge Stephanos Bibas revised his own 2023 decision in February 2025 and found ROSS infringed 2,243 Westlaw headnotes, rejecting its fair-use defence.
  • Bibas said the court was considering "only non-generative AI", and ROSS had built a legal search engine, not a large language model.
  • The US Copyright Office wants voluntary licensing markets to form before Congress considers compulsory measures, while conceding that licensing at training scale is costly and hard to manage.

Why it matters

  • What it limits constraint A company refused a licence by a rival cannot count on a third party's derivative of that data to train a competing product, because the court treated that route as infringement.
  • What it costs cost The licensing bill falls on whoever can afford it; Cryptopolitan and the OECD both expect that to favour companies already holding data, compute and cash.
  • What it sets up precedent Content owners that also sell products built on their data, as Thomson Reuters does with Westlaw, now have an appellate ruling behind a refusal to license a competitor.
  • Who has to decide decision Congress's choice between voluntary and compulsory licensing now decides whether an owner can refuse a rival at all, since only a compulsory scheme would force a sale.

ROSS tried to pay before it copied. Thomson Reuters turned down the licence request because ROSS competed with it [8], so ROSS went to LegalEase and bought almost 25,000 Bulk Memos written from Westlaw headnotes [3]. The court judged that copying by what it was for. "Ross took the headnotes to make it easier to develop a competing legal research tool. So Ross's use is not transformative," Bibas wrote [5].

That sequence makes this an odd licensing precedent to price. Cryptopolitan argues that if AI firms have to pay more for training data, high-quality proprietary content becomes one more advantage for companies with big wallets [16], and the OECD says tight control of data, computing power and other critical inputs already favours the prominent players [11]. The money exists. Goldman Sachs expects global AI investment of about $1 trillion by 2026, with $581 billion of it in the US [12], or about 58% [15]. The US is also where these disputes are being settled one fair-use case at a time [7]. ROSS's problem was a seller that would not sell to a competitor, and a larger budget would not have changed that answer. The cost is a licence fee when the owner will deal, or rather, when the owner is also the competitor, the whole product the buyer meant to build. Cryptopolitan's account of the ruling, drawn from Reuters' September 29 report [1], does not include a damages figure or a licence fee, so that cost cannot yet be put in dollars.

The ruling could stay narrow in two ways, and Congress could override it in a third. The non-generative limit [6] leaves a model developer free to argue that a general-purpose model is a different use from a search engine built to replace its source. The Copyright Office weighs how material was obtained and how its use affects the value of the original [9]. ROSS's facts, derivative memos bought after a refusal and used for a rival product, score poorly on both [8] [3]. Congress could also impose the compulsory licensing that the Copyright Office wants voluntary markets to come before [10].

Europe has built a different system. Rightsholders there can reserve works from text and data mining under Article 4 of the 2019 DSM Directive [13], and in July 2026 the European Commission published a feasibility study for a registry that would help AI developers find those opt-outs through fingerprints, identifiers and metadata [14].

I think the practical effect in the US falls on products built to compete with their data source. Those will license the data or train without it. Two outcomes would prove that wrong: an appellate court finding generative training fair even where the output competes with the source, or a compulsory scheme that forces an owner like Thomson Reuters to sell to a rival at a set rate.

What to watch

  • How the courts hearing the copyright fight over OpenAI and Microsoft treat the ROSS ruling's limit to non-generative AI.
  • Whether the European Commission moves from its July 2026 feasibility study to building an EU registry of text-and-data-mining opt-outs.
  • Any disclosed fee in a voluntary AI-training licence, the first number that would size what this ruling costs a buyer.

Information, not investment advice. This story is general information about companies and markets, drawn from cited reporting. It is not a recommendation to buy, sell or hold any security; check the cited sources before acting.

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Evidence55
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Incentives55
Confidence60

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  1. [1]

    A US appeals court upheld Thomson Reuters' copyright victory against ROSS Intelligence, rejecting ROSS's fair-use defense over its use of Westlaw material to train an AI search engine, Reuters reported on September 29.

    Reported Supported Source: Cryptopolitan, citing ReutersView cited source
  2. [2]

    The ruling is the first US appellate decision on AI-training fair use, and it involved non-generative legal-search technology.

    Reported Supported Source: CryptopolitanView cited source
  3. [3]

    ROSS later procured almost 25,000 'Bulk Memos' sourced from LegalEase, which were created on the basis of Westlaw headnotes.

    Reported Supported Source: CryptopolitanView cited source
  4. [4]

    On February 11, 2025, Judge Stephanos Bibas revisited his 2023 decision and gave Thomson Reuters a victory on its claims of direct infringement and fair use; Bibas indicated the infringement concerned 2,243 headnotes.

    Reported Supported Source: CryptopolitanView cited source
  5. [5]

    "Ross took the headnotes to make it easier to develop a competing legal research tool. So Ross's use is not transformative."

    Reported Supported Source: Judge Stephanos Bibas, as quoted by CryptopolitanView cited source
  6. [6]

    ROSS developed a legal search engine, not a generative large language model, and Bibas indicated that "only non-generative AI" was being considered by the court.

    Reported Supported Source: Cryptopolitan, quoting Judge BibasView cited source
  7. [7]

    The US is largely resolving AI copyright disputes through case-by-case fair-use litigation.

    Reported Supported Source: CryptopolitanView cited source
  8. [8]

    ROSS had sought a licensing agreement for Westlaw content but was denied because it was in competition with Thomson Reuters.

    Reported Supported Source: CryptopolitanView cited source
  9. [9]

    The US Copyright Office considers fair use in generative AI highly fact-dependent; its analysis weighs the material used, how it was obtained, the grounds for copying it, and how the use affects the value of the original.

    Reported Supported Source: US Copyright Office, per CryptopolitanView cited source
  10. [10]

    The Copyright Office supports forming voluntary licensing markets before Congress moves to compulsory measures, while recognising that licensing at AI-training scale can be costly and difficult to manage.

    Reported Supported Source: US Copyright Office, per CryptopolitanView cited source
  11. [11]

    According to the OECD, tight control over data, computing power and other critical inputs gives the upper hand to already prominent players.

    Reported Supported Source: OECD, per CryptopolitanView cited source
  12. [12]

    Goldman Sachs forecasts global AI investment of around $1 trillion by 2026, with $581 billion in the US.

    Reported Supported Source: Goldman Sachs, per CryptopolitanView cited source
  13. [13]

    Under Article 4 of the 2019 DSM Directive, rightsholders can reserve works from text and data mining.

    Reported Supported Source: CryptopolitanView cited source
  14. [14]

    In July 2026 the European Commission published a feasibility study for an EU-level registry that could help AI developers identify text-and-data-mining opt-outs using fingerprints, identifiers and metadata.

    Reported Supported Source: CryptopolitanView cited source
  15. [15]

    The US accounts for about 58% of Goldman Sachs' forecast global AI investment.

    Derived Supported
  16. [16]

    If AI firms are required to pay more for training data, the availability of high-quality proprietary content could become another advantage for companies with big wallets.

    Reported Insufficient Source: Cryptopolitan analysisView cited source
  17. [17]

    Cryptopolitan has reported on the copyright fight surrounding OpenAI and Microsoft, where licensing and fair use are central business issues.

    Reported Insufficient Source: CryptopolitanView cited source

Sources

3 independent publishers whose own reporting we read for this story.

  1. cryptopolitan.com

    1 article · September 29, 2026

    US appeals court upholds Thomson Reuters win in landmark AI copyright case
  2. musicbusinessworldwide.com

    1 article · September 30, 2026

    US appeals court rejects ‘fair use’ defense over AI training – as Thomson Reuters wins copyright case backed by RIAA and NMPA - Music Business Worldwide
  3. pymnts.com

    2 articles · September 29, 2026

    Thomson Reuters Wins AI Copyright Battle

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