IBM Stock Plummets 13% After Anthropic Targets COBOL AI

Shares of International Business Machines (IBM) plunged more than 13% on February 23, 2026, wiping out approximately $31 billion in market value ^[2][4]. The sell-off followed an announcement from AI startup Anthropic regarding new capabilities for its Claude Code tool to automate the modernization of COBOL systems ^[1][3]. Investors reacted to the potential disruption of IBM’s lucrative mainframe consulting business, which manages legacy infrastructure for 95% of U.S. ATM transactions ^[2][4]. ## The Challenge to Legacy Computing Anthropic claims its AI can analyze and document complex COBOL codebases in quarters rather than the years typically required by human consultants ^[1]. By identifying system dependencies and mapping workflows, the tool aims to lower the barrier for organizations to migrate from decades-old mainframes to modern cloud environments ^[1][3]. While IBM has its own AI conversion tools, the market viewed Anthropic’s update as a direct threat to the specialized consulting model that sustains IBM’s legacy profitability ^[3]. IBM responded by emphasizing that while AI can simplify code translation, the true difficulty lies in data architecture and transaction integrity ^[1]. A spokesperson noted that IBM’s deep hardware-software coupling remains a significant hurdle for any automated migration tool ^[1]. Despite this defense, the stock’s decline marked its steepest single-day loss since October 2000 ^[2][4].