10:00verdict at this hour
KOSPI gaps higher at the open, chip stocks sprint; KOSDAQ lags as the market splits by sector
The KOSPI opened at 7,127.77 on Tuesday, August 18 (2026), extended its early gains through the first hour and closed up +2.6% at 7,159.24, driven by a concentrated surge in large-cap semiconductors on the back of an overnight Philadelphia Semiconductor Index (SOX)A U.S. equity index tracking the share prices of companies primarily involved in the design, manufacture, and distribution of semiconductors.Because Korean chip stocks — notably SK hynix and Samsung Electronics — move in close sympathy with U.S. semiconductor valuations, overnight SOX moves are a primary reference for KOSPI gap direction at the open. gain of +1.64%.The KOSDAQ moved in the opposite direction, closing down −0.87% at 857.11 after an intraday range of 13.77 points (1.61%), with foreign investors and institutions both net sellers on that market today.
10:00Snapshot
A window that records the market at that hour, like a photograph
Foreigners provisionally net bought ₩1,069.5bn on the KOSPI today while net selling ₩11.7bn on the KOSDAQ — the gap in flow direction mirrors the index divergence
Top by trading value10— snapshot
A window on how the top trading-value names have moved up to this hour
SK hynix and Samsung Electronics together accounted for over ₩3.28tn of KOSPI turnover in the first hour, with hynix peaking at ₩1,792,000 at 09:39
Through 09:52 KST, SK hynix led KOSPI by traded value at ₩1.98tn, opening at ₩1,740,000 and reaching an intraday high of ₩1,792,000 at 09:39 before easing; Samsung Electronics traded ₩1.30tn, with its intraday high of ₩288,000 also struck at 09:38.On the KOSDAQ, Jusung Engineering (₩128.0bn) and Hana Micron (₩122.6bn) led turnover, with Hana Micron rising +15.71% on a session high of ₩43,350 reached during the session.
| Stock | Prior close | Open | Opening GapThe difference between a security’s or index’s previous close and its opening price the following session, leaving a price range where no trading occurred.A positive opening gap — as seen today with the KOSPI opening at 7,127.77 above Monday’s close — often triggers early momentum buying or, alternatively, gap-fill selling as the session progresses. | High (time) | Last at 10:00 | Change | Low (time) |
|---|---|---|---|---|---|---|---|
| SK hynix | 1,645,000 | 1,736,000 | +5.53% | 1,792,000 (09:39) | 1,767,000 (10:00) | +7.42% | 1,727,000 (09:01) |
| Samsung Electronics | 274,500 | 283,000 | +3.10% | 288,000 (09:38) | 282,500 (10:00) | +2.91% | 281,500 (09:03) |
| Samsung Electro-Mechanics | 1,558,000 | 1,574,000 | +1.03% | 1,595,000 (09:01) | 1,561,000 (10:00) | +0.19% | 1,534,000 (09:03) |
| Samsung Electronics (Pref.) | 195,600 | 197,500 | +0.97% | 202,000 (09:38) | 198,650 (10:00) | +1.56% | 196,800 (09:04) |
| SK Square | 1,154,000 | 1,200,000 | +3.99% | 1,265,000 (09:39) | 1,233,000 (10:00) | +6.85% | 1,175,000 (09:01) |
| LG Electronics | 215,000 | 225,500 | +4.88% | 231,500 (09:01) | 218,000 (10:00) | +1.40% | 216,500 (09:12) |
| Hyundai Motor | 453,000 | 459,500 | +1.43% | 459,500 (09:01) | 455,500 (10:00) | +0.55% | 447,500 (09:04) |
| Kumho E&C | 13,400 | 14,020 | +4.63% | 15,300 (09:11) | 14,130 (10:00) | +5.45% | 14,000 (09:54) |
| Foosung | 12,400 | 12,410 | +0.08% | 14,740 (09:22) | 13,750 (10:00) | +10.89% | 13,000 (09:01) |
| HMM | 21,250 | 21,300 | +0.24% | 23,400 (09:16) | 22,600 (10:00) | +6.35% | 21,350 (09:03) |
Among the notable intraday trajectories, Heosung posted its session high of ₩14,740 at 09:22 before retracing, and HMM hit ₩23,400 at 09:16 — both well above their respective opens — suggesting early momentum faded for several cyclical names after the first 20–25 minutes.LG Electronics showed the sharpest reversal pattern in the top-10: it opened at ₩229,000, printed its intraday high of ₩231,500 at 09:01, then fell to a low of ₩216,500 by 09:12 — a ₩15,000 intraday swing within the first thirteen minutes.
Gainers5· Decliners5— snapshot
A window on the biggest gainers and decliners, and the reasons behind them
Semiconductors lead a split session: KOSPI closes up +2.6% while KOSDAQ slips −0.87%, with SK hynix and Samsung Electronics surging as financials and biotech retreat.
On the KOSPI, gainers included Heosung (+18.47%), Korea Circuit (+14.10%), Hyundai Marine & Fire Insurance (+8.93%), SK hynix (+7.96%), and SK Square (+7.80%) among names with traded value above ₩100bn, while Isu Chemical fell −10.80%, Korea Kolmar −6.29%, and Hanwha Life −3.73%.On the KOSDAQ, Micro Contact Sol rose +29.90%, Ananti +21.39%, Hana Micron +15.71%, HPSP +12.00%, and Padu +12.06%, while TC Materials slid −13.72% and Hyundai Movex −4.82% among names with ₩100bn-plus turnover — underscoring a day where the advance was narrow at the index level but broader within individual KOSDAQ names tied to memory and equipment.