On July 30, South Korea’s KOSPI index bounced back with a staggering 17.9% surge, marking one of the biggest single-day rebounds seen in global markets recently.
Just a day earlier, the same index plunged as much as 12.6% intraday, closing 6% lower, wiping out roughly $2.18 trillion in market value over two sessions. This volatility came after KOSPI more than doubled in the first half of 2026, fueled by soaring demand for AI memory chips.
South Korea’s economy leans heavily on giants Samsung Electronics and SK Hynix, which together make up over half of KOSPI’s market cap. The rollercoaster began when both companies reported earnings that, while strong SK Hynix posted a six-fold profit increase fell short of sky-high investor expectations baked into stock prices. Shares tumbled, with SK Hynix down 9.6% and Samsung 5.2%.
Adding to the turmoil were fears of mounting competition from Chinese chip makers and doubts about whether Big Tech firms would continue aggressive AI infrastructure investments. This combination sent the KOSPI tumbling nearly 40% from its recent peak, erasing months of gains.
The meltdown was amplified by South Korean retail investors, who had piled into leveraged bets on chip stocks. Margin debt hit record highs by June 2026, and as prices dropped, forced liquidations triggered a vicious cycle of selling and margin calls. Leveraged ETFs, popular among traders seeking to magnify exposure, only intensified the swings.
The episode exposes the fragile nature of markets driven by hype around AI and heavy retail participation, especially when concentrated in a few chipmakers. How sustainable the AI boom is remains unclear as investors watch for fresh signals from earnings and global tech spending trends.
This content is for informational purposes and does not constitute financial advice.
