Anthropic’s Legal AI Tool Debut Hits European Data Company Shares

The advance of AI is decimating many other industries.

Anthropic dropped a legal plugin causing some of Europe’s biggest data companies to lose billions in market value.

Thomson Reuters shares crashed nearly 18% in a single day, the UK’s  RELX plummeted 14% and is now trading at half its value from just one year ago—marking its steepest single-day drop since 1988.

The trigger? A plugin released on GitHub that automates legal workflows including contract review, NDA triage, and compliance checks, Law.com reported. Anthropic’s Claude Cowork platform now handles tasks that previously required expensive legal databases and specialized software—and it’s doing so at a fraction of the cost.

The plugin that shattered investor confidence

Two weeks after launching its agentic work mode Claude Cowork, Anthropic rolled out specialized plugins for legal, sales, marketing, and data analysis,

The legal plugin specifically targets in-house counsel workflows and integrates with platforms like Slack, Box, Jira, and Microsoft 365.

What makes this different: Anthropic isn’t just providing an API for legal tech vendors to build on top of—it’s packaging legal workflow products directly into its platform. For the first time, a foundation-model company is competing head-to-head with legal tech vendors who’ve spent years wrapping these same models with playbooks and clause libraries.

The plugin can be customized to match an organization’s specific playbook and risk tolerances, though Anthropic emphasizes outputs require attorney review.

But here’s the part that’s keeping legal tech CEOs up at night: the plugin is completely open source. Corporate legal teams can now customize and build features themselves without waiting for vendors to develop them. The middlemen just became optional.

Who’s bleeding the most value?

Not every legal tech company faces the same threat level. Startups like Harvey and Legora—which attempt to handle broad ranges of legal tasks—are most vulnerable to Anthropic’s new offering. Meanwhile, companies with highly specialized niche focuses will likely remain protected from this disruption.

The market carnage extended far beyond legal-specific companies. Netherlands-based Wolters Kluwer dropped approximately 13%, while U.S. companies Morningstar lost 8% and LegalZoom crashed 19.2%, Reuters data revealed. London-listed firms including Experian, Sage Group, London Stock Exchange Group, and Pearson all fell between 6% and 12%, per Reuters.

Morgan Stanley analysts captured the prevailing sentiment in a recent investor note: most investors they’ve consulted are “overwhelmingly bearish” on Thomson Reuters, worried the company cannot sustain growth in its legal segment amid intensifying competition from specialized AI tools.

Thomson Reuters shares have now fallen 33% year-to-date after dropping roughly 22% throughout 2025, according to Reuters data.

AI’s disruptive power

The panic gripping markets reflects deeper structural concerns about AI’s capacity to disrupt knowledge-based services.

“AI is increasingly able to perform exactly the sort of programming and knowledge-based services that underpin these business models,” Giuseppe Sersale, fund manager at Anthilia, told Reuters.

Traders and analysts note that investor fear often outweighed company fundamentals in yesterday’s (Feb. 3) selling frenzy. But that fear stems from a legitimate question: what happens when foundation models can deliver similar capabilities at a fraction of the cost?

The dramatic market response highlights how quickly AI is reshaping industries once considered safe from automation. Companies that built billion-dollar businesses on legal databases and specialized knowledge are now facing an existential crisis.

At Anthropic and OpenAI, engineers say AI now writes 100% of their production code.

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