The Kospi plummeted nearly 4% to drop back into the 6,500 range today (Sept. 2) as surging international oil prices and U.S. Treasury yields fueled by renewed Middle East tensions dragged down the market.

Although Samsung Electronics and SK Hynix continued their treasury stock purchases today, it was not enough to reverse the downward trend.

The Kospi finished the session down 273.08 points (3.99%) at 6,562.72, returning to a downward trajectory for the first time in three trading sessions since August 28.

The index opened 210.33 points (3.08%) lower at 6,625.47 and briefly narrowed its losses to 6,694.57.

However, the downward pressure soon pushed losses back up.

In the main bourse, foreign investors and institutional investors net-sold 1.9196 trillion won and 2.0437 trillion won, respectively, pulling the index down.

Foreigners and institutions maintained a net-selling streak for four consecutive sessions since August 28.

Conversely, retail investors posted a net-buying advantage of 2.3028 trillion won, while other corporations net-purchased 1.6504 trillion won.

Other corporations extended their buying streak to 11 consecutive sessions through today, driven by Samsung Electronics' treasury stock acquisitions for employee stock compensation and SK Hynix's purchases for treasury stock cancellation.

Supported by net-buying from other corporations, the Kospi had shaken off early session declines to rebound on August 31 and the previous day, displaying a pattern of starting weak and ending strong.

However, heavy selling by foreigners and institutions overpowered the market direction today.

The domestic stock market faced downward pressure as renewed Middle East tensions caused all three major New York stock indices to fall simultaneously, accompanied by steep surges in international oil prices and U.S. Treasury yields.

Following reports of resumed clashes between the U.S. and Iran overnight, the Dow Jones Industrial Average and the S&P 500 index declined 0.79% and 0.71%, respectively, while the Nasdaq Composite index dropped 1.03%.

Consequently, West Texas Intermediate (WTI) crude for October delivery finished up 5.20% at $90.22, while the yield on the 10-year U.S. Treasury note climbed to around 4.79%, marking its highest level since January 2025.

Amidst this, technology sector sentiment also shrank, causing the Philadelphia Semiconductor Index to fall 2.1%.

As this sentiment spilled over into the domestic market, heavy selling flooded in, centered mainly around semiconductor shares.

Although the index losses briefly narrowed during the session thanks to massive buying by other corporations, the market ultimately buckled under the heavier selling pressure from foreigners and institutions.

Lee Kyung-min, an analyst at Daishin Securities, explained, "Despite recent external uncertainties, net-buying from other corporations centered on Samsung Electronics and SK Hynix had supported the lower bound of the index, but today, amid mounting macroeconomic burdens, it was insufficient to offset the selling pressure from foreigners and institutions."

Among large-cap stocks, major semiconductor shares such as Samsung Electronics (-4.02%) and SK Hynix (-4.73%) declined, dragging down the index, while SK Square (-7.97%), Samsung Electro-Mechanics (-2.10%), and LG Energy Solution (-5.31%) also traded weak.

Meanwhile, Meritz Financial Group (3.51%) and Korean Air (0.52%) advanced.

Out of the 911 stocks traded on the Korea Composite Stock Price Index market today, 735 stocks, or 80%, declined.

Only 139 stocks rose, while 37 remained unchanged.

By sector, most industries dropped, including electrical and electronics (-4.34%), transportation equipment and parts (-5.34%), and consumer discretionary (-7.62%), while medical and precision (0.97%) gained.

The Kosdaq index also closed down 17.27 points (2.10%) at 803.98, extending its losing streak to three straight sessions.

The index opened 18.45 points (2.25%) lower at 802.80 and briefly slipped as low as 796.34 (-3.03%), briefly surrendering the 800 threshold.

Losses were partially recovered later as bargain-hunting inflows entered.

Institutions net-sold 232.1 billion won, while individuals and foreigners posted net-buying advantages of 172.7 billion won and 62.9 billion won, respectively.

Among market heavyweights, Alteogen (-0.83%), EcoPro (-5.96%), EcoPro BM (-7.06%), Rainbow Robotics (-2.89%), and Wonik IPS (-0.27%) declined.

Conversely, HPSP, Jusung Engineering (0.40%), EO Technics (2.03%), and ISC (8.53%) advanced.

Due to the sluggish market, the total market capitalization of domestic stock markets (Kospi + Kosdaq + Konex) shrank to 5.8668 trillion won (approx. 5,866.8 trillion won), falling below the 6 trillion won mark for the first time in seven trading sessions since August 24.

However, volatility indices remained stable despite the sharp market plunge.

The Kospi 200 Volatility Index (VKOSPI), referred to as South Korea's "fear gauge," finished down 1.50% at 43.37.

The index has continued a downward trend for eight consecutive sessions from August 24 through today.

Meanwhile, trading value for the day was recorded at 18.575 trillion won for the Kospi market and 5.425 trillion won for the Kosdaq market.

Trading value across the pre-market and main market of alternative trading system Nextrade totaled 8.1777 trillion won.

(Photo: Yonhap News)