South Korean stock market volatility

South Korea’s stock market has swung wildly in recent days, underscoring how the world’s best-performing equity market last year is turning into its most volatile.

criterion Kospi Index It fell 12% on Wednesday, before staging a strong rebound in the next session, rising nearly 10%, marking its biggest one-day drop on record, its best day since 2008. It was down less than 1% on Friday.

Investors are reassessing risks from the escalating war in the Middle East, which has sent oil prices soaring globally and rattled markets, with markets concentrated in some stocks.

The global risk-off mood played a key role, experts said, with concentration in the Korean market’s two memory giants and its sensitivity to energy shocks making it particularly vulnerable to sharp swings.

“If you look at the reaction of other stock markets Korea is a bit of an outlier,” said Jason Hsu, chief executive officer at Reliant Global Advisors. He said the Kospi’s heavy concentration in a handful of technology stocks amplifies market movements compared to more diversified indices.

“It’s natural that the volatility is enormous,” he told CNBC.

SK Hynix, up nearly 45% this year, has soared 274% in the past year. Similarly, Samsung Electronics, up nearly 60% year-to-date, is up 125% in 2025.

They accounted for about a third of the Kospi’s total market capitalization as of early November, according to a report by the Korea Capital Market Institute.

That concentration amplifies volatility: The index can rally quickly when the memory chip cycle is strong, but when investors take profits or sentiment turns risk-off, declines in some of those heavyweight stocks can drag down the entire market, analysts said.

The Kospi volatility index rose 27% to hit a record high on Wednesday at the height of the sell-off. It fell to around 8% on Thursday, but remains at a record high.

Retail leverage amplifies swings

According to market veterans, another factor amplifying the market movement is South Korea’s large base of retail investors and its active derivatives market.

“It’s too much of a leveraged trade that affects the market,” said Daniel Yu, global strategist at Yuanta Securities.

“We had a huge amount of margin calls for retail investors. So they put it out … and then (Thursday) it went up again. It had nothing to do with the fundamentals.”

Retail investors have been among the biggest buyers of Korean stocks since the start of the year, often using margin accounts and through leveraged exchange-traded funds. That means sharp market declines can quickly trigger forced selling as margin calls hit, Yu said.

Individual investors were the largest participants in South Korea’s stock market on Thursday, according to data from the Korea Exchange.

Individual traders sold 19.7 trillion won ($13.3 billion) worth of Kospi shares and bought about 21 trillion won, making them the biggest buyers in the market and leaving them with net purchases of roughly 1.3 trillion won.

Individual investors accounted for the largest share of trading on the Kospi on Thursday, accounting for 45% of total trading, compared with roughly 33% for foreign investors and 22% for institutions, according to Korea Exchange data on Thursday.

Adding to the turmoil is Korea’s sensitivity to energy prices. As a large importer of crude oil, the country is particularly vulnerable to disruptions in global supply.

“Although we have seen sell-offs in major equity markets due to uncertainties surrounding the Middle East, given the relatively high reliance on crude oil imports in South Korea (Tuesday and Wednesday),” said Raisa Rashid, global market strategist at JPMorgan Asset Management.

The semiconductor cycle is still supported

For now, market volatility reflects the unwinding of an overextended rally, said KB Securities’ Kim.

“Given the extent of Korean retail investors’ leveraged positions and the expected prolonged uncertainty from the Iran situation, it is premature to call for an immediate V-shaped recovery,” he said.

But with semiconductor earnings still strong and valuations stabilizing, other market watchers believe the underlying fundamentals of South Korea’s equity market remain intact, particularly in the semiconductor sector, which dominates the index.

“The pullback appears knee-jerk and more emotion-driven at this stage, rather than fundamentally driven,” said Kieran Poon, investment director, Asian equities at Aberdeen Investments.

Memory prices, particularly for dynamic random access memory (DRAM), are rising after a strong 2025 and are expected to support earnings for Korean chipmakers in the first half of 2026, he said.

JPMorgan’s Rashid echoed that view, saying the long-term drivers for Korean stocks remain strong.

“Despite concerns about demand destruction and inventory build-up, demand-supply dynamics in the memory chips space are likely to remain tight this year and possibly into the next,” he said.