A routine update in the field of artificial intelligence has triggered a severe shock in the legal software sector.
The legal plugin launched by Anthropic for its Claude Cowork AI agent last Friday caused a collective plunge in related stocks on Tuesday, with several individual stocks dropping more than 15%.
The new tool developed by the Claude AI chatbot can perform various clerical tasks, including tracking compliance issues and reviewing legal documents. Although this update did not attract much attention outside the legal field, it sparked a sell-off of software and publishing stocks related to the legal industry on Tuesday.
The stocks that suffered heavy losses on Tuesday included: Wolters Kluwer down 13%, RELX down 14%, LegalZoom.com plummeting nearly 20%, and Thomson Reuters down 15%. These stocks have cumulatively dropped at least 20% since the beginning of 2026, with the gradual decline accelerating sharply after the release of the Anthropic legal plugin.
<img src="https://imageproxy.pbkrs.com/https://wpimg-wscn.awtmt.com/0a716cb4-514a-42fd-bc3c-43db1ce63abd.png?x-oss-process=image/auto-orient,1/interlace,1/resize,w_1440,h_1440/quality,q_95/format,jpg" alt="" original-src="https://imageproxy.pbkrs.com/https://wpimg-wscn.awtmt.com/0a716cb4-514a-42fd-bc3c-43db1ce63abd.png"/> (LegalZoom.com plummeting nearly 20%)
Analysts believe that although the threat of AI disruption has been factored into Wall Street's outlook for 2026, investors remain highly vigilant about the impact brought by AI agents.
<h2>Market Position of Claude in Professional Fields</h2>
In the competitive AI market, Claude has become the preferred tool for many legal and financial professionals for analytical work.
According to Business Insider, well-known short-seller Andrew Left stated last year that he used the tool while researching for an upcoming litigation case.
This recognition in the professional field makes the legal-related features launched by Anthropic a more direct threat to existing legal software providers.
Among the affected stocks, only LegalZoom specializes in the legal industry, helping clients streamline tasks by providing guides and independent attorney services.
The UK IT group RELX is involved in the legal field through its legal data and analytics platform LexisNexis. Thomson Reuters' legal business comes from its owned legal research platform Westlaw. Wolters Kluwer also has business in the legal information services sector.
Analysts believe that as AI technology continues to advance, investor confidence in the legal publishing industry may be further undermined.
Reports indicate that in 2025, numerous venture capital firms are competing to invest in legal tech startups, demonstrating the capital market's confidence in these AI-centric companies further disrupting the traditional legal industry.
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RELX

Anthropic's launch of a legal plugin has triggered a sharp decline in legal software stocks, with several individual stocks dropping more than 15%. The plugin can perform document work, and although it has not garnered attention outside the legal field, it sparked a sell-off of related stocks on Tuesday. Affected stocks include Wolters Kluwer, Relx Group, Legalzoom.com, and Thomson Reuters. Analysts believe that while the threat of AI disruption has been incorporated into Wall Street's outlook, investors remain cautious about the impact of AI agents

- A routine update in the artificial intelligence sector caused significant disruption in the legal software market, with stocks plummeting after Anthropic launched its Claude Cowork AI legal plugin.  
- The decline affected companies like RELX, LegalZoom, and Thomson Reuters, many of which saw drops exceeding 15%, leading to a cumulative decline of at least 20% since the beginning of 2026.  
- Analysts express that the rising threat from AI is heightening investor caution, as confidence in the legal publishing sector may further diminish with continued advancements in AI technology.

Wallstreetcn

Why did Anthropic's new tool, which crashed software stocks on Tuesday, have such a powerful impact?