South Korea’s KOSPI index, the darling of global equity markets for most of 2026, just had the kind of two-day stretch that makes financial advisors lose sleep. The benchmark shed roughly $2.18 trillion in market value across July 28 and 29, with an intraday plunge of up to 12.6% before settling for a “mere” 6% loss on the second day. The day before that, it dropped nearly 11%.

What happened, and why it matters beyond Seoul

The catalyst was the AI trade unwinding. Samsung Electronics and SK Hynix, two of the world’s largest semiconductor manufacturers, led the decline as enthusiasm for AI-related chip stocks evaporated.

The KOSPI is now sitting nearly 40% below the peak it reached just over a month ago. For a market that was up 41.5% year-to-date in US dollar terms as of July 29, making it the best-performing major equity market of 2026, that’s a staggering reversal.

Circuit breakers, designed to pause trading during extreme volatility, have been triggered multiple times throughout 2026.

Retail investors caught in the leverage trap

South Korea’s retail investors, nicknamed “ants” in local market parlance, have been piling into leveraged single-stock ETFs tied to semiconductor giants like Samsung and SK Hynix. When the KOSPI started its nosedive, margin calls hit. Forced liquidations followed, with brokerages selling positions whether investors wanted them to or not, locking in losses at the worst possible time.

South Korean Finance Minister Koo Yun-cheol took the unusual step of publicly apologizing to parliament for the impact these leveraged products have had on everyday investors. He also announced plans for regulatory curbs, including potentially capping investments in single-stock leveraged ETFs at 20% of an investor’s portfolio and increasing trading costs for retail participants.

The crypto connection

The proposed 20% portfolio cap on leveraged ETFs is particularly noteworthy from a crypto perspective. South Korea has already implemented strict crypto regulations, including real-name trading requirements and exchange licensing rules. Adding investment restrictions on traditional leveraged products creates a dynamic where both sides of the speculative playground are being simultaneously fenced in.

What investors should be watching

Despite the carnage, the KOSPI’s 41.5% year-to-date gain means investors who bought at the start of 2026 and held through the volatility are still sitting on substantial returns.

Watch Samsung Electronics and SK Hynix closely. These aren’t just Korean bellwethers. They’re global semiconductor supply chain pillars, and if their stock prices continue to slide, it signals something broader about AI infrastructure spending and chip demand expectations that will echo through Nvidia, TSMC, and every AI-adjacent asset class.