KOSPI crosses 6,500 in a sharp July 31 morning rebound

A market update reported that the KOSPI rebounded sharply and crossed 6,500 during the morning of July 31. The reported rise of more than 16% and foreign net purchases of about 4 trillion won were figures from around 10 a.m., not the closing result or a current quotation. Large semiconductor stocks rose strongly after an earlier slump, affecting the overall index, and a temporary restriction on program trading was triggered.

The discussion concerns distinguishing the observation time, sector concentration and cash-versus-futures flows when interpreting large daily moves.