KOSPI and KOSDAQ Surge on Strong Institutional and Foreign Buying

South Korean equities rallied strongly on September 4, 2026, with the benchmark KOSPI climbing 1.64% to close at 6,687.21, and the tech-heavy KOSDAQ surging 2.95% to 813.50. Market sentiment was bolstered by heavy net buying from both foreign and institutional investors, who poured a combined total of over 2.1 trillion KRW into the KOSPI and over 420 billion KRW into the KOSDAQ, while the USD/KRW exchange rate settled at 1,361.14.

Sky Labs Inc. (386380) +135.00%

Price now₩23,500
Prev close₩10,000
Change+135.00%
Mkt cap₩441B
P/E0
P/B0
EPS—
ROE—
Debt ratio—
52W range₩8,200–28,750

Sky Labs Inc. made a spectacular debut on the KOSDAQ market, skyrocketing 135.00% on its first day of trading [1][2][3][4]. The medical device manufacturer attracted massive investor interest due to its specialized focus on ring-type blood pressure monitors [2][3]. Although the stock experienced some early volatility [5], it quickly rebounded to post massive gains. Other specific drivers behind the sharp market debut rally remain unconfirmed [6].

SKSQUARE (402340) +6.12%

SKSQUARE chart

Price now₩1,041,000
Prev close₩981,000
Change+6.12%
Mkt cap₩137.3T
P/E15.66
P/B4.97
EPS₩66,468
ROE85.62%
Debt ratio6.62%
52W range₩144,000–2,189,000

Analyst consensus — 6 ratings, last 180 days · avg target ₩1,880,000

Buy6
Hold0
Sell0

SKSQUARE advanced 6.12% on September 4, continuing its upward movement from earlier in the day [8][9]. This recovery follows downward pressure earlier in the week on September 2, when rising international oil prices dragged down the KOSPI [7] and a US tech sell-off weighed on large semiconductor-related shares [10][11]. While the stock also saw minor gains on September 1 [12], the specific catalysts driving today's strong rebound remain unconfirmed.

ROBOTIS (108490) +22.54%

ROBOTIS chart

Price now₩304,500
Prev close₩248,500
Change+22.54%
Mkt cap₩4.5T
P/E807.69
P/B14.03
EPS₩377
ROE-1.64%
Debt ratio3.04%
52W range₩95,400–464,000

Analyst consensus — 7 ratings, last 180 days · avg target ₩390,143

Buy7
Hold0
Sell0

ROBOTIS surged 22.54% following a highly bullish note from Goldman Sachs, which set a target price of 630,000 KRW [13][14][16]. This optimistic outlook triggered a buying frenzy, with foreign and institutional investors simultaneously net purchasing the stock during the session [15]. This builds on a positive trend from September 3 [17][18], though specific drivers for the previous day's gains remain unconfirmed.

HANMISemiconductorCO.,Ltd. (042700) +9.26%

HANMISemiconductorCO.,Ltd. chart

Price now₩230,000
Prev close₩210,500
Change+9.26%
Mkt cap₩21.9T
P/E103
P/B31.6
EPS₩2,233
ROE33.24%
Debt ratio18.03%
52W range₩82,000–426,000

Analyst consensus — 1 rating, last 180 days · avg target ₩380,000

Buy1
Hold0
Sell0

HANMISemiconductorCO.,Ltd. jumped 9.26% on September 4, surging over 7% during the session to break past the 225,000 KRW mark [19][20]. This sharp rebound follows a period of consolidation on September 1 and 3, where the stock experienced minor, breathing-room declines without any specific negative news [21][22][23][24]. The precise catalysts behind today's sudden double-digit surge remain unconfirmed.

SK Innovation (096770) +5.73%

SK Innovation chart

Price now₩138,300
Prev close₩130,800
Change+5.73%
Mkt cap₩23.4T
P/E-6.57
P/B1.07
EPS₩-21,056
ROE-4.88%
Debt ratio169.73%
52W range₩87,700–155,400

Analyst consensus — 12 ratings, last 180 days · avg target ₩178,917

Buy11
Hold1
Sell0

SK Innovation rose 5.73%, driven by news that its battery subsidiary, SK On, secured a massive 1.5 trillion KRW energy storage system (ESS) supply contract in the United States [25][26][27][28]. The blockbuster deal fueled a multi-day rally starting late August and early September [27][28]. While the stock maintained its upward momentum through September 3 and 4 [29][30], additional specific drivers for the latest session's gains are unconfirmed.

Sources

  1. 스카이랩스, 오늘 코스닥 입성…오전 주가 강세 — 데일리메디 · 2026-09-04
  2. [ET특징주] '반지형 혈압계' 스카이랩스, 코스닥 입성 첫날 140%↑ — 전자신문 · 2026-09-04
  3. 의료기기업체 스카이랩스 코스닥 상장 첫날 장중 주가 공모가보다 114% 급등 — businesspost.co.kr · 2026-09-04
  4. [특징주] 스카이랩스, 코스닥 상장 첫날 16%대 강세 - 조선비즈 — Chosunbiz · 2026-09-04
  5. [속보] 스카이랩스, 장초반 약세 딛고 주가 ‘더블’…주가 변동폭은 유의 — CBC뉴스 · 2026-09-04
  6. 스카이랩스 주가, 급등세... 이유는? — 금강일보 · 2026-09-04
  7. [오늘의 주목주] SK스퀘어 주가 7%대 내려, 코스피 국제유가 급등에 6560선 하락 마감 — businesspost.co.kr · 2026-09-02
  8. SK스퀘어 주가, 9월 4일 장중 1,000,000원 1.94% 상승 — 톱스타뉴스 · 2026-09-04
  9. SK스퀘어 주가 상승 중 — 아시아뉴스통신 · 2026-09-04
  10. SK스퀘어 주가 장중 6%대 내려, 미국 증시 하락에 대형 반도체주 하락세 — businesspost.co.kr · 2026-09-02
  11. SK스퀘어 주가, 9월 2일 장중 1,013,000원 5.06% 하락 — 톱스타뉴스 · 2026-09-02
  12. SK스퀘어 주가, 9월 1일 장중 1,045,000원 0.77% 상승 — 톱스타뉴스 · 2026-09-01
  13. 골드만삭스 목표주가 63만 원 제시 속 로보티즈 주가 급등 — 2news.co.kr · 2026-09-04
  14. 골드만 "로보티즈 63만원 간다"…목표가에 22%대 급등 [핫종목] — v.daum.net · 2026-09-04
  15. [장중수급포착] 로보티즈, 외국인/기관 동시 순매수… 주가 +19.52% — 뉴스핌 · 2026-09-04
  16. [특징주] 로보티즈, 골드만 목표가 63만원에 20% 급등 — 메트로신문 · 2026-09-04
  17. 로보티즈 주가, 9월 3일 장중 259,500원 5.06% 상승 — 톱스타뉴스 · 2026-09-03
  18. 로보티즈, 장중 3%대 껑충…25만4500원으로 상승폭 확대 — CBC뉴스 · 2026-09-03
  19. 한미반도체 주가 장중 7%대 급등…22만5000원선 올라서 — CBC뉴스 · 2026-09-04
  20. 한미반도체 주가 상승 중 — 아시아뉴스통신 · 2026-09-04
  21. [특징주] 한미반도체, 특별한 악재 없이 소폭 하락…숨고르기 양상 : 기업주식정보 — 재경일보 · 2026-09-03
  22. 한미반도체 주가, 9월 3일 장중 210,500원 1.41% 하락 — 톱스타뉴스 · 2026-09-03
  23. 한미반도체 주가 5,500원 하락 후 장마감 — 아시아뉴스통신 · 2026-09-01
  24. 한미반도체 주가, 9월 1일 장중 215,500원 2.27% 하락 — 톱스타뉴스 · 2026-09-01
  25. [ET특징주] SK온 美 ESS 수주 소식에… SK이노베이션 주가 8%↑ — 전자신문 · 2026-09-01
  26. SK온 1.5조원 잭팟에…SK이노베이션 주가 7%대 급등 — 한국경제 · 2026-08-31
  27. SK이노베이션 주가 장중 7%대 올라, 자회사 SK온 ESS 계약에 이틀째 강세 — businesspost.co.kr · 2026-08-31
  28. [특징주] SK이노베이션, 자회사 美 ESS 공급계약에 8%대 강세 — 에너지경제신문 · 2026-09-01
  29. SK이노베이션 주가, 9월 4일 장중 139,000원 6.27% 상승 — 톱스타뉴스 · 2026-09-04
  30. SK이노베이션 주가, 9월 3일 장중 132,800원 0.99% 상승 — 톱스타뉴스 · 2026-09-03

This is market commentary, not investment advice.