TLDR
- Anthropic’s Claude Cowork automation tools launched Friday, targeting legal and business workflows
- Thomson Reuters crashed 18% in its worst single-day drop ever, now down 33% year-to-date
- European legal tech firms RELX and Wolters Kluwer fell 14% and 13% respectively
- Adobe dropped 7.3%, Salesforce lost 6.9% as software sector shed $300 billion in value
- Nasdaq declined 1.43% while advertising stocks Omnicom and Publicis fell over 9%
Stock markets experienced a sharp downturn Tuesday as Anthropic’s new artificial intelligence tools raised concerns about the future of software companies. The AI developer released plug-ins for its Claude Cowork agent last Friday, designed to automate legal, sales, marketing, and data analysis tasks.
Investors reacted swiftly to the news. Thomson Reuters led the decline with an 18% drop, marking its largest single-day loss in company history.
The Toronto-based firm owns Westlaw, a widely used legal research database. Thomson Reuters stock has now fallen 33% in 2026 after declining 22% last year.
Mike Archibald from AGF Investments said Anthropic’s legal-focused plug-ins directly threaten Thomson Reuters’ revenue streams. He explained that markets often sell first and analyze the situation later.
Morgan Stanley analysts reported that most investors they surveyed expressed pessimism about Thomson Reuters. The firm is scheduled to announce fourth quarter earnings results on Thursday.
European Legal Tech Firms Take Heavy Losses
British company RELX fell 14% on Tuesday. The legal analytics provider has lost nearly half its value since peaking in February 2024.
Tuesday’s drop was RELX’s steepest decline since 1988. Dutch competitor Wolters Kluwer dropped 13% during the same trading session.
Other professional services companies also suffered losses. Factset Research declined 10.5% and Morningstar fell 9%.
LegalZoom experienced the steepest drop at 19.7%. In London, Experian, Sage Group, London Stock Exchange Group, and Pearson all lost between 6% and 12%.
Jonathan McMullan from Schroders explained that investors are repricing software stocks. He said AI advancement makes long-term valuations harder to defend when businesses can accomplish more with fewer employees.
Tech Giants and Ad Companies Join Decline
Major technology stocks closed lower on Tuesday. Nvidia fell 2.8% while Meta Platforms dropped 2.1%.
Microsoft lost 2.9% and Oracle declined 3.4%. The software sector collectively lost over $300 billion in market capitalization.
The Nasdaq Composite fell 1.43% to end the session. The S&P 500 declined 0.84% while the Dow Jones dropped 167 points.
Advertising companies faced their own challenges. Omnicom closed down 11.2% in New York.
Publicis, the world’s largest advertising group by market cap, fell more than 9% after reporting earnings. The French company announced plans to spend 900 million euros on AI-focused acquisitions in 2026.
Social media platforms with advertising revenue also declined. Pinterest closed down 5.6% and Snap fell 8.4%.
Giuseppe Sersale from Anthilia said artificial intelligence can now perform the programming and knowledge services these companies depend on. Anthropic’s Claude tools can automate drafting, research, and analysis that previously required expensive software subscriptions.
Adobe fell 7.3% while Salesforce dropped 6.9%. Both companies face questions about their competitive position as AI tools become more capable of handling complex workflows independently.
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