South Korea's benchmark KOSPI index has tumbled into a bear market, sliding roughly 25% from its June peak above 8,000 to below 7,000. The sharp reversal follows a leveraged rally in artificial intelligence-related chip stocks that has now unwound with force, dragging the broader market down.
What Happened
The KOSPI's surge past 8,000 earlier this year was fueled by heavy investor enthusiasm for AI-linked semiconductor companies. But since late June, the index has reversed course, with the selloff accelerating as leveraged positions in two of its biggest components—Samsung Electronics and SK Hynix—began to unwind.
According to Reuters, much of the rally was built on borrowed money and single-stock leveraged products. These financial instruments aim to deliver a multiple of a single company's daily return, amplifying gains on the way up but also magnifying losses on the way down.
Why the Drop Was So Severe
The KOSPI's structure made it particularly vulnerable. Samsung Electronics, the consumer electronics and semiconductor giant, and SK Hynix, a leading memory-chip maker, together account for just over half of the index's weight. That means dramatic moves in either stock can overwhelm the rest of the market.
When SK Hynix shares fell 14% in Seoul, a twice-leveraged ETF tied to the stock dropped more than 30% in Hong Kong. Leveraged funds must rebalance daily, selling more shares after declines to maintain their target exposure. That creates a feedback loop: falling prices trigger margin calls and forced selling, which pushes prices lower still.
South Korea's Financial Supervisory Service has said it will monitor the marketing of these products, and the Bank of Korea has warned that single-stock ETFs could distort trading and increase volatility.
Volatility Spikes
The KOSPI volatility index, which measures expected price swings, surged to 97.99 in late June and remained elevated at 82.07 on Tuesday, far above the 28.85 reading at the end of 2025. That persistent volatility suggests the market is still digesting the aftermath of the leveraged unwind.
For context, a volatility index reading above 30 is generally considered high. The current level indicates traders expect continued large swings in the KOSPI, even if the index stabilizes.
What It Means for Investors
This episode is a reminder that when a market rally is built on leverage, the reversal can be just as dramatic as the ascent. Because Samsung and SK Hynix dominate the KOSPI, forced selling in just those two names can cause index-level moves that feel like a broad market shock, even if most other companies are relatively stable.
For everyday investors, the key takeaway is that leveraged products and margin loans can turn a normal pullback into a rout. The same mechanisms that turbocharge gains in a rising market can accelerate losses when sentiment shifts. Regulators are now paying closer attention, but the structural risk remains as long as these products are widely used.
Investors should also watch how the broader AI trade evolves. The KOSPI's slide does not necessarily mean the AI story is over, but it does show how quickly enthusiasm can turn to panic when leverage is involved. For those with exposure to Korean equities, understanding the role of these two chip giants is essential to interpreting market moves.
In related news, SK Telecom and KT are leading a $12.5 million 5G-AI industrial pilot, highlighting that South Korea's AI ambitions extend beyond semiconductors. Meanwhile, global markets have been navigating their own volatility, with US inflation cooling more than expected in June and Citi posting its best quarterly revenue in a decade amid volatile trading conditions.
Looking Ahead
South Korean regulators are likely to keep a close eye on leveraged product sales and margin lending practices. The Bank of Korea's warning about single-stock ETFs suggests there may be tighter rules ahead. For now, the KOSPI remains in bear market territory, and the elevated volatility index signals that the path to recovery may be bumpy.
Investors should monitor whether the forced selling has run its course or if further unwinding is still to come. The concentration of the index in just two stocks means that any news about Samsung or SK Hynix—whether on chip demand, earnings, or geopolitics—could move the entire market.
