KOSPI and KOSDAQ Surge at Midday as Tech and Energy Lead Gains

South Korean markets are showing strong upward momentum at midday, with the benchmark KOSPI rising 1.41% to 6,672.23 and the tech-heavy KOSDAQ jumping 2.78% to 812.17. The USD/KRW exchange rate is trading at 1,361.14. Investor sentiment is highly positive, driven by strong buying in technology, robotics, and energy sectors.

Sky Labs Inc. (386380) +117.50%

Sky Labs Inc. made a spectacular debut on the KOSDAQ market on September 4, 2026 [1], [2], [3], [4], [6]. The medical device manufacturer, known for developing an innovative ring-type blood pressure monitor, saw its stock price surge by 117.50% at midday, with intraday gains peaking at over 114% above its IPO price [1], [2], [3], [4]. While the listing and its unique product line drove initial interest [1], [2], [3], [4], [6], any additional factors behind the explosive midday rally remain unconfirmed [5].

ROBOTIS (108490) +21.13%

ROBOTIS surged 21.13% on September 4, 2026, propelled by Goldman Sachs setting a bullish target price of 630,000 KRW, which significantly boosted investor sentiment [7], [8], [12]. Additionally, the company is expected to benefit from US regulatory actions targeting Chinese humanoid robots [9]. The upward momentum was further supported by strong, synchronized net buying from both foreign and institutional investors during the session [10]. This follows a steady 5.06% gain in the previous session on September 3 [11].

HANMISemiconductorCO.,Ltd. (042700) +8.79%

HANMISemiconductor rose 8.79% on September 4, 2026, climbing past the 225,000 KRW mark with an intraday jump of over 7% [13], [17]. However, the specific drivers behind today's sharp rise remain unconfirmed [13], [17]. This rally follows a brief consolidation phase on September 3, where the stock dipped slightly by 1.41% to 210,500 KRW without any negative news [15], [16]. The exact reasons for a previous 2.27% decline on September 1 also remain unconfirmed [14], [18].

SK Innovation (096770) +5.20%

SK Innovation advanced 5.20% on September 4, 2026, trading at 139,000 KRW intraday [23]. The stock has maintained upward momentum following a 0.99% gain on September 3 [24] and a major 8% surge on September 1 [19], [22]. This consecutive strength is driven by a massive 1.5 trillion KRW energy storage system (ESS) supply contract secured by its subsidiary, SK On, in the United States, which was announced on August 31 [20], [21].

S-OilCorporation (010950) +7.78%

S-Oil Corporation climbed 7.78% on September 4, 2026, reaching 162,400 KRW intraday as it attempts to break its previous peak price [27], [30]. The stock was boosted by strong net buying from both foreign and institutional investors [28], continuing a trend seen earlier on September 1 [25]. While positive refining margins have supported the sector [26], specific earnings or external factors behind today's rapid rise remain unconfirmed.

Sources

1. [특징주] '반지 혈압계' 스카이랩스, 코스닥 상장 첫날 16%대 '상승' — 글로벌이코노믹 · 2026-09-04
2. [ET특징주] '반지형 혈압계' 스카이랩스, 코스닥 입성 첫날 140%↑ — etnews.com · 2026-09-04
3. 의료기기업체 스카이랩스 코스닥 상장 첫날 장중 주가 공모가보다 114% 급등 — 비즈니스포스트 · 2026-09-04
4. [속보] 스카이랩스, 코스닥 상장 주가 16%↓…의료용 기기 제조업체 — CBC뉴스 · 2026-09-04
5. 스카이랩스 주가, 급등세... 이유는? — 금강일보 · 2026-09-04
6. [특징주] 스카이랩스, 코스닥 상장 첫날 장 초반 6% 상승 — 매일경제 마켓 · 2026-09-04
7. 골드만삭스 목표주가 63만 원 제시 속 로보티즈 주가 급등 — 2news.co.kr · 2026-09-04
8. 골드만 "로보티즈 63만원 간다"…목표가에 22%대 급등 [핫종목] — 뉴스1 · 2026-09-04
9. [특징주] 로보티즈, 美 중국산 휴머노이드 규제 수혜.. '급등' — 글로벌이코노믹 · 2026-09-04
10. [장중수급포착] 로보티즈, 외국인/기관 동시 순매수… 주가 +19.52% — 뉴스핌 · 2026-09-04
11. 로보티즈 주가, 9월 3일 장중 259,500원 5.06% 상승 — 톱스타뉴스 · 2026-09-03
12. [특징주] 로보티즈, 골드만 목표가 63만원에 20% 급등 — 메트로신문 · 2026-09-04
13. 한미반도체 주가 장중 7%대 급등…22만5000원선 올라서 — CBC뉴스 · 2026-09-04
14. 한미반도체 주가 5,500원 하락 후 장마감 — 아시아뉴스통신 · 2026-09-01
15. [특징주] 한미반도체, 특별한 악재 없이 소폭 하락…숨고르기 양상 : 기업주식정보 — 재경일보 · 2026-09-03
16. 한미반도체 주가, 9월 3일 장중 210,500원 1.41% 하락 — 톱스타뉴스 · 2026-09-03
17. 한미반도체 주가 상승 중 — 아시아뉴스통신 · 2026-09-04
18. 한미반도체 주가, 9월 1일 장중 215,500원 2.27% 하락 — 톱스타뉴스 · 2026-09-01
19. [ET특징주] SK온 美 ESS 수주 소식에… SK이노베이션 주가 8%↑ — etnews.com · 2026-09-01
20. SK온 1.5조원 잭팟에…SK이노베이션 주가 7%대 급등 — 한국경제 · 2026-08-31
21. SK이노베이션 주가 장중 7%대 올라, 자회사 SK온 ESS 계약에 이틀째 강세 — 비즈니스포스트 · 2026-08-31
22. [특징주] SK이노베이션, 자회사 美 ESS 공급계약에 8%대 강세 — 에너지경제신문 · 2026-09-01
23. SK이노베이션 주가, 9월 4일 장중 139,000원 6.27% 상승 — 톱스타뉴스 · 2026-09-04
24. SK이노베이션 주가, 9월 3일 장중 132,800원 0.99% 상승 — 톱스타뉴스 · 2026-09-03
25. [장중수급포착] S-Oil, 외국인/기관 동시 순매수… 주가 +2.00% — 뉴스핌 · 2026-09-01
26. [특징주] 정유株, 정제마진 호재에도 숨고르기…SK이노·S-Oil 약세 — v.daum.net · 2026-09-02
27. S-Oil 주가, 9월 4일 장중 162,400원 9.80% 상승 — 톱스타뉴스 · 2026-09-04
28. [장중수급포착] S-Oil, 외국인/기관 동시 순매수… 주가 +9.67% — 뉴스핌 · 2026-09-04
29. S-Oil(010950) — 매일경제 마켓 · 2026-09-01
30. [속보] ＇8만원→16만원＇ 쑥 올랐다…다시 ＇최고가＇ 돌파 넘보는 S-Oil — 한국경제TV · 2026-09-04

This is market commentary, not investment advice.