[Edaily Reporter Park Sun-Yeop ] The KOSPI plunged nearly 10%, falling below the 8,200 mark. The index, which had shown strength early in the session by rising to the 9,170 level, abruptly reversed course as profit-taking selling pressure surged, particularly in large-cap semiconductor stocks. As selling pressure spread rapidly, sell-side circuit breakers were triggered in both the KOSPI and KOSDAQ markets, and a circuit breaker was also activated in the KOSPI market.
According to MP Doctor on the 23rd, the KOSPI closed at 8,203.84, down 910.71 points (9.99%) from the previous trading day. The index rose as high as 9,175.45 early in the session but subsequently extended its losses, eventually closing just above the 8,200 level.
Sell-side circuit breakers were triggered in both the KOSPI and KOSDAQ markets that day. This marks the 27th time this year that a circuit breaker has been triggered in the KOSPI market and the 15th time in the KOSDAQ market. A circuit breaker was also triggered in the KOSPI market. This marks the fourth circuit breaker this year and the 10th in history. This was driven by extreme market volatility as selling pressure concentrated on large-cap semiconductor stocks, which had led the index’s recent rally.

In terms of supply and demand, selling pressure from foreign investors and institutions drove the index lower. Institutions recorded net sales of 5.8302 trillion won, while foreign investors recorded net sales of 5.6969 trillion won. In contrast, retail investors recorded net purchases of 11.4194 trillion won. This marks the largest-ever net purchase by retail investors. Program trading, combining arbitrage and non-arbitrage transactions, showed a net selling position of 6.6801 trillion won.
The securities industry interpreted the day’s sharp decline as a correction from the market’s concentration on large-cap semiconductor stocks rather than a shift in market fundamentals. This is because major macroeconomic indicators—such as oil prices, U.S. Treasury yields, and the dollar—did not fluctuate sharply, and declines in overseas markets, including U.S. Nasdaq futures and Japan’s Nikkei, were limited.
Han Ji-young, an analyst at KIWOOM Securities, said, “It is difficult to view this as a resurgence of external negative factors, such as the breakdown of ceasefire negotiations or concerns over the Fed’s monetary tightening,” adding, “It appears to be a short-term side effect resulting from the concentration of trading in semiconductor stocks.” She explained, “The concentration of trading was particularly severe the previous day amid the competition between SamsungElectronics and SK hynix for the top market capitalization spot, and volatility intensified today as profit-taking pressure, led by foreign investors, grew stronger.”
He continued, “Selling volume from leading stocks appears to be increasing downward pressure on other sectors and KOSDAQ stocks where bid-ask spreads have narrowed,” but added, “This correction is largely driven by technical issues such as speed and market concentration, and it is difficult to view it as a signal of a market peak or a bubble burst.”
Lee Kyung-min, an analyst at DaishinSecurities, also analyzed, “The domestic stock market turned bearish as profit-taking selling emerged from large-cap semiconductor stocks that had been driving the uptrend,” adding, “Factors such as the failure to be included in the MSCI Developed Markets Index, discussions on taxation of unrealized gains, and caution ahead of Micron’s earnings release all contributed to a contraction in investor sentiment.”
Lee Jae-man, Head of Global Investment Analysis at Hana Securities, noted that volatility could increase as earnings expectations rise. He said, “High earnings growth rates create optimism, but they can also fuel concerns about earnings falling short of expectations and growth rates peaking,” adding, “Given the recent rise in the VIX, we need to be cautious about increased volatility.”
He went on to explain, “Applying the 20-day deviation low of 94%—which was observed in early June when concerns over a Fed rate hike were prominent—the market bottom would be around the 7,900 level.”
By market capitalization, large-cap stocks saw the sharpest decline, falling 10.31%. Mid-cap and small-cap stocks also fell by 5.54% and 4.41%, respectively. By sector, the electrical and electronics sector underperformed the most, falling 11.92%. The manufacturing and healthcare/precision instruments sectors also fell by 11.04% and 10.37%, respectively. In contrast, the food, beverages, and tobacco sector and the real estate sector saw relatively smaller declines, falling by 1.41% and 2.49%, respectively.
Most of the top market-cap stocks also traded lower. SK hynix(000660)closed at 2,555,000 won, down 364,000 won (12.47%) from the previous trading day. SamsungElectronics(005930)closed at 310,000 won, down 43,500 won (12.31%).
In addition, SKSQUARE(402340)(-7.01%), SamsungElectroMechanics(009150)(-10.68%), HyundaiMotor(005380)(-12.05%), Samsung Life Insurance(032830)(-5.66%), LG Energy Solution(373220)(-6.10%), and SAMSUNG C&T CORPORATION(028260)(-12.50%) also fell.
Trading volume on the KOSPI market that day totaled 483.71 million shares, with a total trading value of 59.8624 trillion won. Including four stocks that hit their upper price limit, 46 stocks rose, while 859 fell. No stocks hit their lower price limit, and 13 remained unchanged.
The KOSDAQ index also plummeted. The KOSDAQ index closed at 891.52, down 76.88 points (7.94%) from the previous trading day. Although it surpassed the 970 mark early in the session, it subsequently extended its losses, falling to the low 890s.
In the KOSDAQ market, retail investors were net sellers of 4615억 won worth of stocks. Foreign investors and institutions were net buyers of 3126억 won and 1357억 won, respectively. Program trading, combining arbitrage and non-arbitrage transactions, showed a net buying position of 2507억 won.