On October 1, South Korean stocks staged a strong rebound on the first trading day of the fourth quarter. Although weighed down by external factors such as soaring U.S. Treasury yields, the Korea Composite Stock Price Index (KOSPI) opened with choppy small losses and briefly fell below the 6,800 mark, but then reversed into positive territory under strong support from institutional buying. Optimism over artificial intelligence (AI) demand was ignited by better-than-expected earnings from U.S. memory chip giant Micron Technology, and combined with robust domestic semiconductor exports, chip sector bulls erupted across the board, driving the index higher throughout the session to close near its highest point of the day.

The KOSPI opened today at 6,814.49 points and touched an intraday low of 6,765.06 points. It then surged strongly on heavy institutional buying. By the close, the KOSPI had jumped 133.31 points, or 1.95%, to finish at 6,971.35 points, successfully ending a three-session losing streak. The KOSDAQ index performed even more explosively, soaring 38.38 points, or 4.48%, to close at 894.29 points.

Micron's Earnings Bonanza Ignites the "Two Chip Giants"

Micron Technology's previously released strong results and additional supply chain commitments completely cleared away the market's pessimism. South Korea's local semiconductor giants surged in response, with Samsung Electronics closing up 2.79% and SK hynix gaining 3.21%, serving as the absolute engine of the day's market counterattack.

Institutional Money Steps Up to Absorb Market Selling Pressure

In today's trading, although foreign investors and retail investors recorded net selling pressure of 548.5 billion won and 1.43 trillion won respectively, institutional investors demonstrated strong control, recording net buying of 334.5 billion won for the day, successfully building support at low levels and igniting a bullish counterattack.

Broad Sector Gains and Active Theme Stocks

Beyond semiconductors, heavyweight sectors such as medical precision instruments (up 5.65%), pharmaceuticals (up 2.89%), and electrical and electronics (up 2.84%) also led gains, with biopharmaceutical giants Celltrion and Samsung Biologics each recording gains of about 3%. In addition, after U.S. President Trump publicly disclosed South Korea's investment plan for an Alaska liquefied natural gas (LNG) project, related concept stocks such as Daehan Steel and Dongkuk Steel also saw collective sharp moves in the afternoon.