IBM Shares Plummet 13% as Anthropic's AI Threatens Mainframe Business

• IBM shares dropped 13.2% in a single day, marking its worst performance since March 2020, due to Anthropic's new AI tool.
• Anthropic's 'Claude Code' can modernize systems running on COBOL, a language that has been IBM's 'golden goose' for decades.
• COBOL-based mainframe systems, primarily sold and maintained by IBM, still power 95% of US ATM transactions.
• AI's ability to quickly and cheaply convert COBOL code threatens IBM's long-standing business model, which relied on the complexity and cost of modernizing these systems.
• The 'Claude Code Security' feature also impacted cybersecurity stocks, as investors fear AI's disruption across traditional sectors.