Anthropic's launch of new Claude Cowork automation plug-ins on Friday, February 4, 2026, triggered a massive selloff in software and data analytics stocks, erasing over $300 billion in market value in a single session. The tools, designed to automate legal, sales, marketing, and data analysis tasks, were perceived as a direct threat to the core business models of established companies that charge premium prices for these services.
The selloff was led by legal and professional services firms. Thomson Reuters stock plummeted 18%, tracking toward its largest single-day loss on record. The company's shares have now fallen 33% year-to-date, following a 22% decline in 2025. Portfolio manager Mike Archibald of AGF Investments stated the plug-ins "directly challenge Thomson Reuters’ core legal business." Morgan Stanley analysts reported widespread investor bearishness, with concerns the company cannot maintain growth in its legal segment against specialized AI competition.
European legal analytics providers were hit hard. British firm RELX dropped 14%, marking its worst day since 1988, with shares now nearly 50% below their February 2024 peak. Dutch company Wolters Kluwer fell 13%. Other professional services firms also suffered: Factset Research declined 10.5%, Morningstar lost 9%, and LegalZoom plummeted 19.7%.
The panic spread to broader technology and advertising sectors. Major tech stocks declined, with Nvidia down 2.8%, Meta Platforms falling 2.1%, Microsoft losing 2.9%, and Oracle declining 3.4%. The Nasdaq composite fell 1.43% and the S&P 500 dropped 0.84%. In advertising, Omnicom closed down 11.2% and France's Publicis dropped over 9% despite announcing plans to spend 900 million euros on AI and data-focused acquisitions in 2026. Pinterest fell 5.6% and Snap dropped 8.4%.
Jonathan McMullan of Schroders explained the selloff reflects "a deepening structural debate" where AI advancement erodes the "visibility premium" of traditional software models and threatens per-user licensing. Giuseppe Sersale of Anthilia added, "Artificial intelligence is increasingly able to perform exactly the sort of programming and knowledge-based services that underpin these business models."
Amid the market turmoil, Anthropic's valuation continues to climb. A source familiar with the matter indicated the AI company is arranging a deal allowing employees to sell shares at a valuation of at least $350 billion, concurrent with a funding round aiming to raise over $20 billion. This contrasts sharply with the struggles of its newly threatened competitors.
