[Edaily Reporter Kwon Oh Seok ] The KOSPI closed higher on the 27th, rising to the point where a temporary suspension of program buy orders (the “buy-side car”) was triggered. News that U.S. artificial intelligence (AI) company Anthropic is moving forward with an initial public offering (IPO) reignited investor enthusiasm for AI, benefiting not only the New York Stock Exchange overnight but also the KOSPI.

According to MP Doctor on the 27th, the KOSPI opened at 5,658.65, up 189.18 points (3.46%) from the previous trading day, and closed at 5,638.34, up 168.87 points (3.09%).
During the KOSPI’s regular trading session that day, retail investors were the only net sellers, offloading 949.2 billion won, while foreign and institutional investors were net buyers of 592.7 billion won and 282.1 billion won, respectively. By trading type, combined arbitrage and non-arbitrage trades showed a net buying position of 627.8 billion won.
As the KOSPI rose more than 4% intraday to reach 5,737.61, the buy-side circuit breaker was triggered around 10:13 a.m. due to volatility in the KOSPI 200 futures index. According to the Korea Exchange, this marks the 53rd time the mechanism has been triggered this year, and it was triggered again for the first time in four trading days since the 21st. At the time of activation, the KOSPI 200 futures index stood at 893.02, up 43.00 points (5.05%) from the previous day’s closing price.
The KOSPI buy-side sidecar is triggered when the KOSPI 200 futures price rises by 5% or more from the benchmark price and remains at that level for one minute. It remains in effect for five minutes from the time of activation and is automatically deactivated after five minutes have elapsed.
Earlier, Anthropic, the U.S.-based developer of the generative AI chatbot “Claude,” filed a registration statement (Form S-1) with the U.S. Securities and Exchange Commission (SEC), marking the start of its full-scale IPO process. The proposed ticker symbol is “ANT,” and Goldman Sachs and Morgan Stanley are serving as lead underwriters for the listing. The specific number of shares to be offered and the proposed price range will be determined at a later date.
Lee Kyung-min, an analyst at DaishinSecurities, noted, “The domestic stock market staged a rebound as bargain-hunting buying, centered on AI semiconductors, flowed in. While the recovery in AI investment sentiment had been delayed, the release of Anthropic’s S-1 filing served as a catalyst for a turnaround in market sentiment.”
Consequently, buying momentum poured into the market, particularly in large-cap domestic semiconductor stocks. During regular trading that day, SamsungElectronics(005930)closed at 222,000 won, up 9,000 won (4.23%) from the previous trading day, while SK hynix(000660)closed at 1,341,000 won, up 66,000 won (5.18%).
The analyst noted, “Improved investor sentiment toward AI drove the index’s strength, which was led by the semiconductor sector,” adding, “There is also anticipation ahead of SK hynix’s earnings announcement scheduled for the following day (the 28th).”
Meanwhile, the KOSDAQ index opened at 743.09, up 15.88 points (2.18%) from the previous trading day, and closed at 743.83, up 16.62 points (2.29%).
In the KOSDAQ market that day, retail investors were the only net sellers, offloading 166.1 billion won, while foreign and institutional investors were net buyers of 19.1 billion won and 150.4 billion won, respectively. By trading type, combined arbitrage and non-arbitrage trades showed a net buying position of 44.2 billion won.