Relx (REL) led a broader sell-off across professional data services, media and software stocks on Tuesday, slumping as much as 16 per cent after AI group Anthropic released a set of 鈥榓gentic鈥 productivity tools for its Claude Cowork platform.
The company launched 11 open-source plug-ins, published on GitHub late last week. Among them was a legal workflow tool designed to automate contract reviews, compliance checks and legal research, tasks Relx charges pricey subscription fees for through its legal information and analytics platform, LexisNexis.
But Relx wasn鈥檛 the only victim. The market sold off almost every company that relies on selling specialised professional data on fears that increasingly capable general purpose AI 鈥榓gents鈥 could start doing much of the same work at a fraction of the cost, eroding pricing power across the sector.
The group鈥檚 main US rival Thomson Reuters (US:TRI) fell nearly 16 per cent and European peer Wolters Kluwer (AMS:WKL) dropped 13 per cent. London Stock Exchange Group (LSEG) slid 13 per cent, Pearson (PSON) lost 7 per cent and Experian (EXPN) was down 6.7 per cent.
Claude鈥檚 plug-ins also include tools for analysing financial data and building forecasting models, researching sales prospects, drafting marketing content, running enterprise search, handling customer support, assisting product management and even supporting biology research.
Advertising agencies were also hit hard. WPP (WPP) fell 12 per cent, Publicis (FR:PUB) slid 9 per cent and Omnicom (US:OMC) was down 11 per cent. London-listed software groups were dragged down too, with accounting software firm Sage (SGE) down nearly 10 per cent.
Shares in fund manager Nick Train鈥檚 Finsbury Growth & Income (FGT) investment trust, which has suffered a prolonged stretch of poor performance, also fell on Tuesday. At the end of last year, the trust鈥檚 top 10 holdings included Relx, LSEG, Experian and Sage, which he sees as quality companies with high margins and defensive moats.




