Why IBM stock lost $31 billion in a few hours because of Anthropic

After Anthropic published an article claiming that its Claude Code tool could now drastically accelerate the modernization of applications written in COBOL, IBM quickly felt the effects.

Indeed, the American group saw its stock price fall by more than 13% in a single session, marking its worst daily performance since October 2000. A brutal drop that wiped out nearly $31 billion in market capitalization in just a few hours. But behind this spectacular reaction, the subject is far from new…

Claude Code attacks the historical heart of IBM

COBOL (Common Business-Oriented Language) is a language designed in the late 1950s, and which remains today at the heart of critical infrastructures such as bank payments, airline systems, or even public administrations. According to Anthropic, nearly 95% of ATM transactions in the United States still rely on this language. The problem is well-documented, with COBOL developers becoming increasingly scarce, technical debt accumulating, and migration projects notoriously complex and expensive. In a blog post, Anthropic claims that Claude Code can map millions of lines, identify dependencies, document business processes, and, most importantly, automate some of the analysis work that makes these transformations lengthy and costly. For investors, while AI facilitates the modernization of legacy systems, the business model of solutions like these... IBM could be weakened…

A threat that IBM is already anticipating…

An impressive fall… – Source: Google

The stock market reaction contrasts sharply with the strategic reality, because the subject is not a surprise for IBM. As early as 2023, the group launched its own AI-based conversion tool, watsonx Code Assistant for Z, specifically designed to support the modernization of COBOL to newer environments like Java.

Last month, Arvind Krishna, IBM's CEO, highlighted the business's record performance, the highest in twenty years. He attributed this momentum in part to AI-powered automation and conversion solutions. In other words, the modernization of COBOL does not necessarily threaten IBM, but could also fuel its digital transformation business.

A long road ahead for modernization…

Finally, IBM and Anthropic cannot ignore one reality: modernizing a banking or administrative system is not simply a matter of converting code. Whether it concerns governance, regulatory compliance, audits, or even human validation, this modernization will not be so easy.

And while this advance marks the beginning of an evolution, this new episode primarily illustrates a trend where, in the markets, the perception of a technological breakthrough can produce immediate effects.