IBM shares suffered their most severe single-day decline in nearly four decades, plunging 26% in US trading on Tuesday.
The collapse marks the steepest drop for the technology giant since the 1987 market crash, wiping out billions in market value in a single session.
The sell-off was triggered by the company's preliminary profit warning for the second quarter, which disappointed investor expectations and sparked a broad-based liquidation of the stock.
The magnitude of the move underscores the market's sensitivity to execution risks in large-cap technology names.
With the stock down a quarter of its value, the decline represents a significant repricing of IBM's near-term earnings potential.
The sharp drop also highlights the vulnerability of legacy tech firms facing pressure to deliver consistent growth in a competitive landscape.