On the 29th, after starting higher in early trading, the KOSPI and KOSDAQ indexes swung sharply lower, triggering simultaneous sell-side program quote suspensions (sell-sidecars).
The semiconductor bellwether SK hynix(000660)'s second-quarter results announcement that day and the previous day's steep drop in U.S. semiconductor stocks appear to have worked in combination, freezing investor sentiment.
As of 11:26 a.m. that day, the KOSPI was down 338.77 points (5.62%) from the previous trading day at 5684.89. After topping the 6200 level and rising early in the session, the index even lost the 5700 mark amid worsening individual flows. At 10:55 a.m., the KOSPI200 futures index plunged 5.15% from the previous trading day, triggering a sell-sidecar on the Korea Exchange securities market.
At the same time, the KOSDAQ index was also down 42.64 points (6.04%) from the previous trading day at 663.21. At 10:56 a.m., the KOSDAQ150 futures index fell 6.21%, triggering a sell-sidecar on the KOSDAQ market as well.
By investor type, individuals led the decline. On the Korea Exchange, individuals were net sellers of 1.8401 trillion won, engaging in large-scale dumping. Institutions and foreigners were net buyers of 1.4362 trillion won and 46.3 billion won, respectively, absorbing supply, but it has not been enough to defend the index.
The market took a direct hit from a steep sell-off in semiconductor bellwethers, including SK hynix. SK hynix announced record results that day on a consolidation basis for the second quarter of this year, with revenue of 79.3187 trillion won and operating profit of 60.5426 trillion won, but the stock plunged.
Operating profit jumped 557% from a year earlier, but it came in about 5% below the securities industry's estimate (63.5 trillion won), falling short of the market's heightened expectations.
On the previous day in the U.S. market, a China-related drag and concerns about artificial intelligence (AI) profitability triggered a broad plunge in semiconductor stocks, which, combined with the situation, led to a flood of profit-taking and dumping by individual investors.
After rising early in the session, SK hynix slid 9.35% to 1,405,000 won. Among large-cap names, Samsung Electronics (-4.55%), Samsung Square (-9.73%), Samsung Electro-Mechanics (-8.26%), and SK (-9.61%)—semiconductor and related group stocks across the board—have all been unable to avoid broad weakness.