IBM shares collapsed in US trading on Tuesday, plunging 26% to record their most severe single-day decline since the 1987 market crash.
The sell-off was triggered by the company's preliminary profit warning for the second quarter, which signaled results significantly below analyst expectations.
The sharp repricing wiped out billions in market value in a matter of hours, reflecting deep investor concern over the tech giant's near-term earnings trajectory.
The magnitude of the drop underscores the market's sensitivity to any deviation from consensus estimates for large-cap technology names.
With the stock falling nearly a quarter of its value, the move represents a historic breach of support levels that have held for decades.
The volatility highlights the fragility of the current valuation multiple, which had been sustained by expectations of steady growth in its hybrid cloud and AI segments.