[Edaily Reporter Kim Kyung-eun ] The KOSPI fell more than 5% during trading on the 30th, dropping to the 5,600 level. This was driven by a wave of selling centered on major semiconductor stocks such as SamsungElectronics and SK hynix, as concerns about the profitability of artificial intelligence (AI) investments spread following earnings reports from major U.S. tech companies. As KOSPI 200 futures prices plummeted during the session, the “sell-side car,” which temporarily suspends the execution of program sell orders, was triggered.

According to MP Doctor, as of 1:01 p.m. that day, the KOSPI was trading at 5,658.86, down 278.80 points (4.70%) from the previous trading day. The index opened at 5,760.35, down 177.31 points (2.99%) from the previous session, and the decline accelerated. At one point during the session, it fell as much as 5.70% to 5,599.42, briefly dipping below the 5,600 mark.

At 10:04:55 a.m. today, a sell-side sidecar was triggered in the KOSPI market. This marks the second trading day since the buy-side sidecar was triggered on the 28th, and it is the 28th time a sidecar has been triggered in the KOSPI market this year. The sell-side sidecar is a mechanism that suspends the effectiveness of program sell orders for five minutes if the KOSPI 200 futures price remains down more than 5% from the previous trading day for at least one minute.

Behind the sharp stock market decline lie concerns about the profitability of AI investments, which surfaced following earnings reports from major U.S. tech companies. Google’s parent company, Alphabet, reported earnings that fell short of market expectations, and the widening deficit in free cash flow (FCF) dampened investor sentiment. Amazon also announced earnings and guidance that fell below market expectations, highlighting the cost burden associated with large-scale AI capital expenditures.

Kang Jin-hyuk, a senior analyst at Shinhan Investment Securities, analyzed, “A sell-off centered on the AI value chain occurred due to the impact of consecutive earnings disappointments in sectors such as Big Tech and semiconductors.”

By investor type, both foreign and institutional investors continue to sell off shares. As of this writing, foreign investors are net sellers of 1.0977 trillion won, while institutions are net sellers of 89.1 billion won. Although retail investors are absorbing the selling pressure with net purchases of 1.01 trillion won, their efforts appear insufficient to stem the index’s decline.

Most of the top-market-cap stocks are down. SamsungElectronics(005930)is trading at 219,500 won, down 5.39% from the previous trading day. SK hynix(000660)is down 7.67% at 1,409,000 won. Semiconductor-related stocks are also seeing sharp declines, including SKSQUARE(402340)(-7.35%) and SamsungElectroMechanics(009150)(-10.21%).

Defense stocks are also weak. HANWHA AEROSPACE(012450)is plummeting 12.37%. The fact that third-quarter operating profit fell 46% year-over-year to 452 billion won—due to delays in defense export deliveries and exchange rate fluctuations—weighed on the stock price.

In contrast, #SAMSUNG BIOLOGICS (3.88%), Celltrion(068270)(0.74%), and SAMSUNG SDI CO.,LTD.(006400)(0.19%) are showing slight gains.

By sector, the declines were particularly pronounced in electrical and electronics (-6.17%), medical and precision instruments (-7.21%), and machinery and equipment (-4.42%).

The KOSDAQ index is also down by more than 4%. At this time, the KOSDAQ is trading at 722.56, down 30.67 points (4.07%) from the previous trading day. The index opened 2.05% lower and fell as low as 717.27 during the session.

In the KOSDAQ market as well, foreign and institutional investors are net sellers of 73.9 billion won and 94.5 billion won, respectively. Retail investors are net buyers of 175.2 billion won.

Among the top market-cap stocks, Alteogen Inc.(196170)(-2.05%), ECOPRO CO., LTD(086520)(-1.91%), ECOPRO BM CO., LTD.(247540)(-1.85%), Rainbow Robotics(277810)(-3.84%), EO Technics Co., Ltd.(039030)(-6.39%), and LEENO Industrial Inc(058470)(-9.08%) are all down. In contrast, HLB INC.(028300)is up 0.13%.