Korea's bourse operator on Wednesday activated a sell-side sidecar for the benchmark Korea Composite Stock Price Index (KOSPI) after the index fell sharply, led by tech losses. Program trading in KOSPI-listed shares was suspended for five minutes around 10:55 a.m., according to the Korea Exchange (KRX). The KOSPI fell by more than 4.5 percent. The decline came as retail investors sold off large-cap stocks, including SK hynix, as investors question whether massive spending on artificial intelligence (AI) will generate returns enough to justify elevated tech firms' valuations. A sell-side sidecar is triggered when the KOSPI 200 Futures Index falls 5 percent or more for at least one minute.