South Korea KOSPI Crashes 7.49% as SK Hynix Falls 11%

South Korea’s stock exchange triggered a temporary trading halt on Thursday after the benchmark KOSPI index plunged more than 5%, as a technology-led sell-off on Wall Street and persistent US inflation intensified concerns about higher interest rates.

The KOSPI fell 7.49%, or 450.02 points, to 5,558.79 as of 7:05 a.m., extending its losing streak to seven consecutive sessions. This marked the index’s longest run of declines since September 2024.

The sharp sell-off was led by major technology companies, with SK Hynix shares plunging 11.06% and Samsung Electronics falling 9.05%. Losses across heavyweight chipmakers dragged the broader market lower as investors reassessed their exposure to technology stocks amid growing uncertainty over global monetary policy.

The exchange activated its sell-side sidecar mechanism after a steep decline in index futures. The measure temporarily suspends programme sell orders for five minutes to help contain sudden market volatility.

Why Did South Korea Trigger a Trading Halt?

The immediate trigger was a sharp fall in stock index futures, which activated South Korea’s automatic sidecar mechanism for programme selling.

The sidecar is designed to slow automated selling when futures prices move rapidly. Rather than closing the entire stock market, it temporarily suspends programme sell orders for five minutes, giving market participants time to respond to extreme price movements.

The mechanism was activated as investors reacted to a technology-led sell-off on Wall Street. Stronger-than-expected US inflation data heightened expectations that the Federal Reserve could keep interest rates elevated for longer or consider further increases.

Higher interest rates can put pressure on technology stocks by increasing borrowing costs and reducing the present value investors assign to companies’ expected future earnings. These effects can be particularly significant for growth stocks whose valuations depend heavily on anticipated profits.

The combination of global technology-sector weakness and uncertainty over US monetary policy contributed to the broad decline in South Korean equities.

SK Hynix and Samsung Electronics Lead the Sell-Off

South Korea’s heavyweight chipmakers were among the hardest-hit stocks during Thursday’s market rout.

• SK Hynix: Shares plunged 11.06% as selling intensified across the technology sector.
• Samsung Electronics: Shares fell 9.05%, adding significant pressure to the benchmark index.
• LG Energy Solution: Shares declined 3.44%.
• Hyundai Motor: Shares dropped 3.99%.
• Kia Corp: Shares fell 2.03%.

The losses reflected broader investor caution rather than weakness confined to semiconductor companies. As major technology stocks came under pressure, declines spread across other important sectors of South Korea’s equity market.

Mixo Das, head of Korea equity strategy at JPMorgan in Hong Kong, told Reuters that the market was struggling to attract new buyers after share buyback programmes at Samsung Electronics and SK Hynix had run their course.

“The market is struggling to find a new buyer,” Das said, highlighting the difficulty of sustaining share prices without continued buying support.

Despite the short-term volatility, Das maintained a positive longer-term outlook for artificial intelligence-related stocks. He said he expected these shares to be substantially higher over a six-to-12-month horizon.

His comments highlighted the contrast between immediate market pressures and longer-term expectations for AI-related demand, which has supported investor interest in semiconductor companies.

Broad-Based Selling Hits South Korean Stocks

The market decline extended well beyond the largest technology companies, with the majority of traded stocks moving lower.

Of the 889 stocks traded, 768 declined, while only 90 advanced. The breadth of the losses indicated that selling pressure was widespread across the market rather than concentrated in a small group of companies.

Foreign investors were net sellers of South Korean shares worth 355.6 billion won, adding to the pressure on domestic equities.

Investors were weighing the potential impact of higher US interest rates on global capital flows, corporate valuations and demand for risk-sensitive assets. Uncertainty surrounding the technology sector also contributed to the cautious mood.

The sharp declines in Samsung Electronics and SK Hynix were particularly significant because of their influence on the benchmark index and their importance to South Korea’s semiconductor industry.

South Korean Won Strengthens Despite Stock Market Rout

South Korea’s currency moved in the opposite direction to equities, strengthening against the US dollar despite the sharp decline in share prices.

The won was quoted at 1,339.5 per dollar, up 0.21% from its previous close of 1,342.3. The currency’s movement contrasted with the steep losses in the stock market, highlighting differences in how investors were responding across asset classes.

Government bond yields also declined as investors assessed the implications of inflation and the outlook for interest rates.

• Three-year Korean Treasury bond yield: Fell 3 basis points to 3.855%.
• 10-year Korean Treasury bond yield: Declined 2.1 basis points to 4.224%.

The fall in bond yields suggested a different market response from the selling pressure seen in equities. Currency and bond movements can reflect a range of factors, including changing expectations for monetary policy, demand for financial assets and investors’ assessments of economic risks.

US Inflation and Interest Rate Expectations Remain in Focus

The latest market turmoil underscores the influence of US inflation data on Asian equities. Stronger inflation can increase the likelihood of tighter monetary policy, potentially affecting borrowing costs, investment decisions and valuations across global financial markets.

Technology companies are particularly sensitive to changes in interest rate expectations because investors often value them based on earnings expected further into the future. When yields rise, those future earnings can become less attractive in present-value terms.

For South Korea, the impact is especially important because semiconductor companies account for a significant share of market activity and investor attention. A sharp sell-off in major chipmakers can therefore have an outsized effect on the broader benchmark.

What Investors Will Watch Next

Investors will monitor whether the KOSPI can stabilise after its seven-session losing streak and whether buying interest returns to major semiconductor stocks.

Developments in US inflation, Federal Reserve policy expectations and global technology shares are likely to remain key influences on market sentiment. The return of sustained buying support could help ease pressure on Korean equities, while further uncertainty over interest rates may prolong volatility.

Although JPMorgan strategist Mixo Das remains optimistic about AI-related stocks over the longer term, the immediate market outlook remains uncertain as investors navigate global monetary policy concerns, broad-based selling and weakening confidence in major technology shares.