Both companies beat on the top and bottom lines on Thursday evening. Amazon closed the regular session at $235.50 and traded up to roughly $252 after hours, a gain of about 7% at the print and 9% at the peak. Apple closed at $333.43 and traded down to roughly $312, a decline of more than 6%. The divergence had almost nothing to do with the quality of the two beats and almost everything to do with a single input cost that both companies discussed at length: DRAM.

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.