IBM closed down 25.2% at $217.07 on July 14, the steepest single-day decline in the company’s history and the worst drop in records that run back to 1968 — worse than the 23.7% collapse of October 1987. Roughly $67 billion in market value evaporated on a preliminary second-quarter print that missed revenue by 3.7%. That gap between the size of the miss and the size of the reaction is the entire story. The market did not sell a quarter. It repriced the forward earnings stream.