KOSPI Closes at 7,080.92 Up 0.9% as Samsung Leads Into Chuseok After Giving Back Open

SEOUL — South Korea's KOSPI finished Sept. 23 at 7,080.92, up 63.01 points, or 0.90 percent, after an opening spike above 7,150 faded into pre-holiday selling.

The session was the last before the four-day Chuseok harvest break. The market is scheduled to reopen Sept. 28. The index opened at 7,153.99, the day's high, then slid to 7,014.98 before chip buying pulled it back through the 7,000 handle. It was the fourth straight advance and the highest close since late July in some local tallies.

Samsung Electronics rose 3.25 percent to 285,500 won, closing above 280,000 won for the first time since July 10, Aju Press reported. SK hynix gained 1.20 percent to 1,862,000 won after touching 1.9 million won at the open. SK Square, which holds a large SK hynix stake, jumped about 5 percent. Samsung Electro-Mechanics also finished higher.

The tape was narrow. Aju Press counted 548 decliners against 311 advancers on the main board. Institutions were net buyers of about 318.8 billion won. Retail investors sold about 1.44 trillion won. Foreigners sold about 510.6 billion won after buying earlier in the day, according to Digital Today and matching exchange flow figures carried by other Seoul desks. One News1-based rundown said foreigners still bought 1.28 trillion won of Samsung Electronics even as they were net sellers of the broader market, while individuals sold more than 2 trillion won of Samsung.

Overnight U.S. semiconductor strength set the open. SBS cited a 2.06 percent rise in the Philadelphia Semiconductor Index, with Micron up 5 percent and Nvidia higher. Digital Today said early buying also reflected expectations for server DRAM demand. The Korea Times, in a morning wrap from Yonhap, linked the open to back-to-back Nasdaq records and reports of easier Middle East tensions that helped oil ease.

The won was quoted at 1,359.00 per dollar in Digital Today's close, weaker by 3.50 won, or 0.26 percent. The KOSDAQ rose 10.10 points, or 1.21 percent, to 844.48.

WSJ data put the day's range at 7,014.98 to 7,153.99 and the prior close at 7,017.91. The 52-week range in that table ran from 3,365.73 to 9,385.59. Year-to-date the index was still sharply higher on a 2026 rally that had already peaked well above 9,000 in June before giving back ground in the third quarter.

What the close does not settle is whether chip leadership survives the holiday. Samsung's quarterly dividend calendar and guidance, Micron's late-September results and U.S. labor data sit on the other side of Chuseok in local event lists. Those are dates, not forecasts. Retail selling of more than 1 trillion won in a single session, after several days of individual selling measured in the trillions, is profit-taking into a break, not a verdict on memory pricing.

The KOSPI is still a semiconductor index in practice. Samsung and SK hynix dominate capitalization. When they open 2 to 3 percent higher, the benchmark prints 7,150. When individuals sell the same names into the afternoon, 7,080 is what is left. Institutions bought the dip. Foreigners flipped from morning buyers to afternoon sellers. That is the flow print.

Four sessions of gains put the index back over 7,000 after a choppy September that included a drop through 6,600 mid-month. The June high remains far above Wednesday's close. The one-year change is still more than a double from the year-ago level near 3,500 in long-run data series.

For three days the market is shut. The last print is 7,080.92, Samsung at 285,500 won, SK hynix at 1,862,000 won, and a won rate near 1,359. That is the board Korea takes into Chuseok.