The KOSPI’s retreat exposed how record retail borrowing and extreme concentration in two semiconductor companies could turn a change in market expectations into a forced-selling cycle.

The index closed 2025 at 4,214.17 and more than doubled over the next six months, reaching a record close of 9,114.55 on June 22. It then fell to 5,647.65 by Wednesday morning.

Near the peak, Samsung Electronics and SK Hynix represented almost 55% of the KOSPI’s total market value, while outstanding margin loans reached a record $26.7 billion (38.63 trillion won) two trading sessions after the index topped.

The rally rested on