IBM Stock Crashes 13% as Anthropic’s Claude AI Targets Legacy COBOL Dominance

By Tech Markets Desk | February 23, 2026

New York – Shares of International Business Machines Corp. (IBM) plunged more than 13% on Monday, erasing much of the company’s recent gains and marking its steepest single-day drop in over 25 years, after AI startup Anthropic unveiled a powerful new tool for modernizing outdated COBOL systems—a cornerstone of IBM’s enterprise software business.[1][2][3]

IBM’s stock closed at $223.35, down 13.15% for the session, in its biggest one-day percentage loss since October 2000. The tumble leaves the shares down 27% for February alone, positioning the month for IBM’s worst performance since at least 1968, according to market data.[1][5]

Anthropic’s Claude Code Disrupts COBOL Legacy

The catalyst was Anthropic’s announcement of enhanced capabilities in its Claude AI model, specifically the Claude Code tool, designed to automate the analysis and modernization of COBOL—Common Business-Oriented Language—a decades-old programming language still powering critical systems in banking, insurance, and government operations.[2][3][4]

COBOL, known for its English-like syntax and reliability in high-volume data processing, runs on many mainframes, where IBM holds significant market share through its zSystems hardware and related services. Businesses have long struggled with the high costs of maintaining and updating these legacy systems, often delaying modernization efforts because analysis alone could take months or years.[2][3]

“Legacy code modernization stalled for years because understanding legacy code cost more than rewriting it. AI flips that equation,” Anthropic stated in a blog post.[2]

Anthropic claims Claude Code can map dependencies across thousands of lines of code, document workflows, identify risks that would take human analysts months to uncover, and deliver insights to accelerate decision-making. “With AI, teams can modernize their COBOL codebase in quarters instead of years,” the company added.[1][3]

Broader AI-Driven Software Sell-Off Continues

The news hit amid an ongoing AI-fueled sell-off in software stocks that began earlier in February. Anthropic’s prior release of legal AI plugins had already rattled legal tech firms, prompting investors to reassess exposure to sectors vulnerable to generative AI disruption.[2]

Monday’s market reaction amplified concerns. Tech stocks broadly declined, influenced by tariff uncertainties and circulating reports on AI’s potential negative impacts. DoorDash shares also sank after a viral research post labeled it a “poster child” for AI agent risks, while biotech Arcellx soared on a $115-per-share acquisition by Gilead Sciences.[1]

Key Stock Movements on February 23, 2026

Company	Change	Close Price	Notes
IBM	-13.15%	$223.35	Biggest drop since 2000[1][5]
DoorDash (DASH)	Down	N/A	AI agent risks highlighted[1]
Arcellx (ACLX)	+78%	All-time high	Gilead acquisition[1]

IBM’s Vulnerability Exposed

IBM has positioned itself as an AI leader through its Watson platform and hybrid cloud services, but its reliance on legacy mainframe revenue makes it susceptible to AI tools that promise cheaper alternatives for system overhauls. The new Anthropic feature directly challenges IBM’s consulting and modernization services, which generate substantial revenue from COBOL-dependent clients.[3][4]

Analysts note that while AI modernization tools aren’t new, Anthropic’s scale and speed—powered by its Claude large language model—represent a credible threat. “This poses a potential threat to the kind of business data service that comprises a core part of IBM’s business,” one report observed.[2]

Prior to Monday, IBM shares had climbed steadily, buoyed by enterprise AI demand. The sell-off wiped out most of those gains, raising questions about the sustainability of Big Tech’s legacy businesses in an era of rapid AI advancement.[3]

Market Implications and Investor Reactions

Investor sentiment turned sharply negative, with trading volume spiking as funds rotated out of software names perceived as AI-disruptable. Bloomberg’s Closing Bell highlighted IBM’s plunge alongside broader market movers, underscoring the event’s significance.[1]

StockTwits and other platforms buzzed with commentary, with users pointing to Anthropic’s blog as the trigger. “IBM Stock Tumbled More Than 13% Today — What’s Anthropic Got?” one headline captured the surprise.[3]

Business Insider framed it as part of a persistent software rout, noting COBOL’s obscurity outside tech circles but its outsized impact on enterprise giants like IBM.[2]

Looking Ahead: AI’s Double-Edged Sword

For IBM, the episode highlights the double-edged nature of AI: a growth driver in some areas, but a disruptor in others. The company may accelerate its own AI offerings for legacy systems to counter competitors like Anthropic, backed by Amazon and Google.

Meanwhile, the incident signals to Wall Street that no tech incumbent is immune. As AI tools proliferate, investors are recalibrating valuations across sectors reliant on human-intensive processes, from coding to compliance.

IBM did not immediately respond to requests for comment on the Anthropic development or its stock movement. Anthropic emphasized its tool’s efficiency gains without directly addressing competitive implications.

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