Why did South Korea's KOSPI plummet? The 6th circuit breaker triggered this year, has the semiconductor cycle turning point arrived?

On July 7, 2026, the Korea Composite Stock Price Index (KOSPI) experienced a complete cycle from extreme panic to partial recovery. The index opened at 7,919.20 points, down 1.64% from the previous trading day, and lost the 8,000-point mark shortly after the opening. The decline intensified in the afternoon, with KOSPI plunging over 8% intraday, triggering the exchange's circuit breaker mechanism and halting all market trading for 20 minutes.

By the close, KOSPI stood at 7,656.31 points, down 395.02 points or 4.91% from the previous trading day. Compared to the recent high of 9,385.59 points, KOSPI has retreated about 18%, technically approaching bear market territory. Heavyweight stocks Samsung Electronics and SK Hynix both fell over 6%, with intraday losses exceeding 10% at one point. Against a backdrop of record-high earnings, why did the Korean stock market suffer such a severe sell-off?

Sixth Circuit Breaker of the Year: What Happened in the Korean Stock Market on July 7

On July 7, the Korean stock market experienced two triggers of market safety mechanisms. Around 10:23 a.m., as KOSPI 200 futures fell 5%, the Korea Exchange activated the "sell sidecar" mechanism (program trading suspended for 5 minutes). The decline worsened in the afternoon; around 1:51 p.m., KOSPI's decline expanded to over 8% and lasted more than one minute, prompting the exchange to activate the first-level circuit breaker, suspending all stock trading for 20 minutes. This was the sixth time the Korean stock market triggered a circuit breaker in 2026.

In terms of intraday movement, KOSPI opened at 7,919.20 points, reached an intraday high of 7,954.55 points, then continued to decline to a low of 7,389.22 points. After the circuit breaker, the index stabilized near the low and rebounded, finally closing at 7,656.31 points. From the intraday high of 7,954.55 points to the low of 7,389.22 points, the full-day range was as high as 565.33 points. Trading volume on the main board that day reached 5.12294 billion shares, with a turnover of approximately 39.66 trillion won.

The main drag on the market was undoubtedly the semiconductor sector. Samsung Electronics fell nearly 10% intraday, while SK Hynix's intraday decline exceeded 11% at one point. Semiconductor stocks have a very high weight in KOSPI, and the sharp declines of these two chip giants directly drove the index lower.

Earnings Surge 18 Times, Why Did Samsung Electronics Face Capital Flight?

On the morning of July 7, Samsung Electronics released its preliminary earnings for the second quarter of 2026. The data showed that Samsung Electronics' consolidated revenue for the second quarter reached 171 trillion won, up 129% year-on-year; operating profit reached 89.4 trillion won, up 1,810.3% year-on-year, setting a new quarterly profit record for the third consecutive quarter. This result not only exceeded the market expectation of 87.3 trillion won but was also 19 times that of the same period last year.

However, this historically remarkable earnings report did not boost the stock price. Samsung Electronics closed at 296,000 won on that day, down 22,000 won or 6.92% from the previous trading day. It briefly fell below the 300k won mark intraday, hitting a low of 287,500 won. SK Hynix closed at 2,201,000 won on the same day, down 142,000 won or 6.06%. Both stocks fell over 10% at some point intraday.

Analysts mainly attributed the selling pressure to typical "buy the rumor, sell the news" and profit-taking. Samsung Electronics and SK Hynix had accumulated substantial gains in the first half of the year. With such large unrealized profits, any fundamental uncertainty could trigger massive profit-taking. Han Ji-young, an analyst at Kiwoom Securities, pointed out that after Samsung Electronics' preliminary earnings announcement, the "sell on the news" logic dominated in the short term, while leveraged ETFs on individual stocks also accelerated the decline as supply-demand distortion factors.

Is the Semiconductor Cycle Approaching an Inflection Point?

Samsung Electronics' "sell on the news" is not an isolated event; it is a microcosm of the recent continuous pressure on the global semiconductor sector.

The Philadelphia Semiconductor Index has fallen nearly 12% from its high. Morgan Stanley's chief equity strategist noted in a recent report that momentum in the semiconductor sector has clearly faded recently, with funds shifting from semiconductors to AI supercomputing giants like Microsoft, Amazon, and Meta, as well as consumer and biotech sectors. U.S. hedge funds have been net sellers of semiconductor and tech hardware stocks for four consecutive weeks. On July 6, memory and semiconductor stocks experienced a massive intraday sell-off, marking the most dramatic single-day reversal in AI hardware trading since the 2022 bear market.

Concerns about "excess computing power" are growing. With SK Hynix and Samsung announcing a series of long-term investment plans, and Meta also planning to sell excess computing power, the market has become worried about potential oversupply risks in the chip and computing power market.

However, there is clear divergence in the market regarding the inflection point. Nomura analysts said in a recent report that market concerns about "excess computing power" may be overdone, and the memory chip industry still has a long way to go before the downcycle. Nomura specifically pointed out that the massive investment projects announced by Korean chip giants may not have a material impact on supply for several years—SK Hynix's Yongin semiconductor cluster project, initiated nine years ago, has not yet been fully operational and will only begin small-scale production by the end of 2027. JPMorgan strategists similarly stated that weakness in semiconductors should be viewed as a buying opportunity, as the chip cycle has not yet peaked, and meaningful new supply is not expected until 2028. Local Korean securities research firms also generally believe that the recent correction in semiconductor stocks is a short-term speed adjustment rather than a fundamental deterioration.

How Did the Attack on Merchant Ships in the Strait of Hormuz Disturb Global Risk Assets?

Geopolitical risk was the third straw that crushed the Korean stock market.

According to a report by Axios on July 6, Iran's Islamic Revolutionary Guard Corps fired at least two missiles at several merchant ships passing through the Strait of Hormuz, hitting two ships and causing severe damage. The UK Maritime Trade Operations Office reported the same day that an oil tanker was hit by an "unidentified projectile" in the Gulf of Oman and caught fire.

The Strait of Hormuz is one of the world's most important oil transport routes, with about one-third of global seaborne oil trade passing through it. Iran's military actions in these waters directly increased the global geopolitical risk premium. For South Korea, which is heavily dependent on energy imports, tensions in the Strait of Hormuz have direct economic security implications. Rising geopolitical risks typically trigger two types of capital behavior: first, global capital flows from emerging markets to safe-haven assets; second, capital with higher risk appetite reduces exposure to cyclical and export-oriented economies. As a typical export-oriented stock market, the Korean stock market usually bears greater selling pressure during geopolitical conflicts.

Continued Foreign Capital Outflows: The Other Side of KOSPI's First-Half Surge

The selling pressure on the Korean stock market did not start on July 7. The sustained foreign capital outflows had already set the stage for this crash.

On July 7, foreign investors net sold 2.9173 trillion won on the Korean main board, while institutional investors net sold 3,092 billion won during the same period. This marked the 13th consecutive trading day of net foreign selling of Korean stocks. In stark contrast, individual investors net bought 3.1343 trillion won that day, becoming the only bullish force in the market, but failed to reverse the overall downward trend of the index.

The anomaly here is that while foreign capital was withdrawing on a large scale, KOSPI surged over 100% in the first half of the year, ranking first among major global stock indices. Korea Investment & Securities noted that the market value of foreign holdings in KOSPI increased far more than the index itself, and the proportion of foreign-held market value to total market capitalization rose to the highest level since the global financial crisis.

Goldman Sachs pointed to more structural issues. For every 1 percentage point increase in the combined weight of Samsung Electronics and SK Hynix in the Korean stock index, foreign investors might withdraw about $2 billion from the Korean market. This is because the U.S. Investment Company Act requires portfolios to meet diversification thresholds, and as the stock prices of these two chip giants soared, the concentration of the Korean stock index has reached worrying levels. The pressure from foreign rebalancing, exchange rate risk, and profit-taking formed a triple selling motivation.

The continued depreciation of the Korean won further reinforced this trend. On July 7, the won-dollar exchange rate in the Seoul foreign exchange market stood at 1,528.2 won, up slightly by 2.1 won from the previous trading day. Although the won rebounded slightly that day, it had previously fallen to its lowest level since 2009. Every time foreign investors sell Korean stocks, they need to convert won into dollars for repatriation, directly increasing selling pressure on the won; and the more the won depreciates, the more foreign investors tend to sell stocks and exit to avoid exchange losses. Moon Da-woon, an economist at Korea Investment & Securities, bluntly stated: "It is difficult to expect foreign investors to turn into net buyers of domestic stocks in the second half of the year; this is an inevitable backlash from the rapid rise of KOSPI."

From Seoul to the World: The Contagion Effect of the Korean Stock Market Crash

The crash in the Korean stock market quickly spread to global capital markets.

The Nikkei 225 index closed down 2.12% on the day, at 68,256.96 points. Semiconductor-related stocks were under significant pressure—Japan's NAND leader Kioxia plunged over 11%, and SoftBank closed down over 3%. In the Hong Kong market, the CSOP Double Long Samsung Electronics ETF and the CSOP Double Long SK Hynix ETF both fell over 15%.

As the world's major supplier of memory chips, sharp volatility in the Korean stock market is often seen as a barometer of the global semiconductor industry's health. Samsung Electronics and SK Hynix dominate the global DRAM and NAND flash memory markets. The stock price movements of these two companies not only reflect investor judgment on the Korean market but also reflect the global pricing of the semiconductor cycle outlook. When Korean chip giants face selling amid record earnings, global investors have reason to reassess the valuation logic of the entire semiconductor sector.

Market Divergence: Cyclical Correction or Structural Shift?

There is a clear divergence in the market's interpretation of the crash on July 7.

Optimists view this as a normal correction within the semiconductor supercycle. Samsung Electronics' second-quarter operating profit grew 1,810% year-on-year; this growth rate itself indicates that the industry's fundamentals remain strong. Memory chip shortages remain a key bottleneck for AI development, and manufacturers are prioritizing production of high-end memory to meet data center demand. Analysts expect this shortage to last at least until the end of 2027. Against this backdrop, recent selling is more of a technical adjustment driven by profit-taking rather than a signal of fundamental deterioration. Kiwoom Securities analyst Han Ji-young also noted that given the index has been pushed down to levels where a valuation rebound could occur, maintaining existing stock weights and positions is better than panic selling.

Cautious observers worry that the capital expenditure race in the semiconductor industry is accumulating oversupply risks. As giants like Samsung and SK Hynix continue to expand capacity, there is uncertainty about whether the expansion of AI data centers can sustainably absorb this new supply. In addition, the persistent foreign outflows and the depreciation pressure on the Korean won constitute structural negatives for the Korean stock market, which will not disappear after one circuit breaker. Korea Securities researcher Oh Jae-young warned that the potential sellable holdings of foreign investors "are estimated to be no less than the amount already sold."

Summary

The crash of the KOSPI index on July 7, 2026, which plunged over 8% intraday triggering a circuit breaker and eventually closed down 4.91% at 7,656.31 points, was the result of multiple factors converging. Samsung Electronics and SK Hynix experienced "sell on the news" selling after record earnings, closing down 6.92% and 6.06% respectively, reflecting growing market concerns about the semiconductor cycle inflection point; Iran's military actions in the Strait of Hormuz raised global geopolitical risk premiums; and the contrast between 13 consecutive days of foreign capital outflows and individual investors' counter-trend net buying of 3.1343 trillion won in a single day highlighted the structural pressures that cannot be ignored in the Korean stock market. From Seoul to Tokyo and Hong Kong, the ripple effects of this crash have already appeared. Whether the semiconductor cycle is a phased correction or a trend reversal remains a matter of debate, but it is certain that the high volatility of the Korean stock market will not subside easily in the short term.

FAQ

Q: What was the final close of the KOSPI index on July 7?

A: On July 7, the KOSPI index closed at 7,656.31 points, down 395.02 points or 4.91% from the previous trading day. It hit an intraday low of 7,389.22 points, a decline of 8.22%, triggering the circuit breaker.

Q: Why did Samsung Electronics' stock price plunge despite surging earnings?

A: Samsung Electronics' second-quarter operating profit reached 89.4 trillion won, up 1,810% year-on-year, a record high. However, market analysis suggests that the strong earnings had already been priced into the stock, and investors chose to take profits upon the earnings release. Additionally, the market began focusing more on the longer-term trajectory of the memory chip cycle rather than a single quarter's results.

Q: What was the capital flow of foreign investors and retail investors on July 7?

A: On that day, foreign investors net sold 2.9173 trillion won, and institutional investors net sold 3,092 billion won, marking the 13th consecutive day of net foreign selling. Individual investors net bought 3.1343 trillion won, becoming the only bullish force in the market.

Q: Why did the Strait of Hormuz incident affect the Korean stock market?

A: The Strait of Hormuz is one of the world's most important oil transport routes. Iran's attack on merchant ships in those waters directly increased the global geopolitical risk premium. South Korea is highly dependent on energy imports, and geopolitical conflicts typically cause global capital to flow from emerging markets to safe-haven assets. As an export-oriented economy, the Korean stock market bears greater selling pressure.

Q: Has the semiconductor cycle peaked?

A: There is divergence in the market. Nomura believes that concerns about "excess computing power" are overdone, and the memory chip industry still has a long way to go before a downcycle. JPMorgan also states that the chip cycle has not yet peaked. However, some argue that the capital expenditure race is accumulating oversupply risks and that semiconductor sector momentum has clearly waned.