KOSDAQ Gains Ground While KOSPI Slips on Heavy Foreign Selling

The South Korean stock market closed mixed on September 10, 2026, with the KOSPI declining 0.25% to 7,033.92, while the tech-heavy KOSDAQ rose 0.79% to 836.92. Foreign investors heavily offloaded equities, recording net-sales of KRW 2.48 trillion on KOSPI and KRW 1.07 trillion on KOSDAQ, while institutional buying provided support. The USD/KRW exchange rate finished the session at 1,340.86.

TSE CO.,Ltd (131290) +14.15%

TSE surged 14.15% on September 10, building on recent momentum. The stock's strong performance is driven by rebalancing demand that boosted the semiconductor materials, parts, and equipment sector [1]. Additionally, investor sentiment was lifted by Shinhan Investment's positive earnings outlook and its target price of KRW 400,000 [3], alongside a rising trend in the LED equipment theme [5]. While the stock hit an intraday high of KRW 296,000 [4], the specific immediate catalyst for today's sharp jump remains unconfirmed from the available headlines.

NEXTEEL (092790) +7.96%

NEXTEEL gained 7.96% on September 10, experiencing a strong buying influx that triggered a volatility interruption (VI) during the trading session [7, 8]. The stock drew market attention after being highlighted as one of the promising "tomorrow's whale stocks" in local media on September 9 [9, 10]. However, the specific business developments or underlying fundamental catalysts driving today's sharp upward movement remain unconfirmed by the provided headlines.

PenetriumBio (187660) +11.86%

PenetriumBio climbed 11.86% on September 10, continuing its rapid upward trajectory. The stock had previously hit the daily limit-up price on September 9, triggering two volatility interruptions (VI) [11, 13, 14]. It maintained its momentum on September 10, rising 9.30% intraday [15, 16]. Despite the dramatic price movement, the specific underlying driver or corporate announcement behind this multi-day rally remains unconfirmed from the headlines [12, 16].

GS Engineering & Construction Corp (006360) +4.78%

GS Engineering & Construction Corp rose 4.78% to close at KRW 37,250 on September 10 [22]. The stock has been supported by optimism surrounding potential US-South Korea nuclear power plant cooperation [21] and consistent institutional backing, marked by five consecutive days of net buying [19]. Although the stock saw strong intraday gains [20], any specific new catalyst directly triggering today's 4.78% surge remains unconfirmed.

HD HYUNDAI MARINE SOLUTION CO., LTD (443060) +9.03%

HD Hyundai Marine Solution surged 9.03% on September 10. Prior to this jump, the stock had experienced a weak and sluggish trend due to a lack of clear positive catalysts [23, 26], falling for two consecutive days and struggling to maintain the KRW 210,000 level [27]. Although some minor intraday buying was observed earlier in the week [24], the specific underlying reason or driver for today's sudden 9.03% rebound is unconfirmed in the provided headlines.

Sources

1. 주성엔지·티에스이 10% 급등…리밸런싱 수요에 소부장 강세 — 한국경제 · 2026-09-10
2. 티에스이 주가, 9월 7일 261,500원 10.57% 상승 마감 — 중앙이코노미뉴스 · 2026-09-07
3. [리포트 브리핑]티에스이, '실적 추이 및 전망' 목표가 400,000원 - 신한투자증권 — 뉴스핌 · 2026-09-07
4. 티에스이 주가, 9월 10일 장중 296,000원 10.24% 상승 — 중앙이코노미뉴스 · 2026-09-10
5. 특징주, 티에스이-LED장비 테마 상승세에 6.34% ↑ — 매일경제 · 2026-09-07
6. 티에스이(131290) — 씽크풀 AI · 2026-09-07
7. 넥스틸 주가, 급등세... 무슨 회사길래? — 금강일보 · 2026-09-10
8. [속보] 넥스틸 VI 발동 주가 급등흐름 — CBC뉴스 · 2026-09-10
9. [고래사냥] 'DB하이텍·동진쎄미켐·넥스틸! 내일장 고래 종목은?! - 머니투데이 — 머니투데이 · 2026-09-09
10. [고래사냥] 'DB하이텍·동진쎄미켐·넥스틸! 내일장 고래 종목은?! — supple.kr · 2026-09-09
11. [주가] 9월 9일 주요 제약·바이오·기기 5% 변동 현황 - 페니트리움바이오 상한가 — 메디파나뉴스 · 2026-09-09
12. 페니트리움바이오 주가, 상한가... 왜? — 금강일보 · 2026-09-09
13. [속보] 페니트리움바이오 주가 상한가 도달…VI 두 차례 발동 — CBC뉴스 · 2026-09-09
14. 페니트리움바이오, 상한가 진입.. +29.95% ↑ — 서울경제 · 2026-09-09
15. 페니트리움바이오 주가, 9월 10일 장중 8,110원 9.30% 상승 — 중앙이코노미뉴스 · 2026-09-10
16. 페니트리움바이오 주가, 급등세... 이유는? — 금강일보 · 2026-09-10
17. GS건설 주가, 9월 9일 35,550원 0.85% 상승 마감 — 톱스타뉴스 · 2026-09-09
18. GS건설 주가 하락중 — 아시아뉴스통신 · 2026-09-10
19. [장중수급포착] GS건설, 기관 5일 연속 순매수행진... 주가 +3.12% — 뉴스핌 · 2026-09-09
20. GS건설 주가, 9월 10일 장중 36,650원 3.09% 상승 — 중앙이코노미뉴스 · 2026-09-10
21. 한미 원전협력?...대우건설·GS건설·현대건설·원전주 '장중 껑충' — 초이스경제 · 2026-09-08
22. GS건설 주가, 9월 10일 37,250원 4.78% 상승 마감 — 톱스타뉴스 · 2026-09-10
23. [특징주] HD현대마린솔루션, 뚜렷한 호재 부재 속 약보합세 이어가 : 기업주식정보 — 재경일보 · 2026-09-07
24. [특징주] HD현대마린솔루션, 장중 소폭 상승...특정 호재 없이 수급 주목 : 기업주식정보 — 재경일보 · 2026-09-08
25. HD현대마린솔루션 투자분석 2026. 09. 06 — 주달 · 2026-09-06
26. HD현대마린솔루션, 뚜렷한 동력 없이 약보합권서 소폭 상승 마감 : 기업주식정보 — 재경일보 · 2026-09-08
27. HD현대마린솔루션, 이틀 연속 하락세 마감…21만원선 수성 분투 : 기업주식정보 — 재경일보 · 2026-09-09

This is market commentary, not investment advice.