KOSPI and KOSDAQ Plunge Midday While MLCC and Quantum Tech Sectors Rally

The South Korean stock market experienced a sharp downturn by midday, with the benchmark KOSPI falling 2.47% to 6,860.17 and the tech-heavy KOSDAQ dropping 2.24% to 818.16. Meanwhile, the USD/KRW exchange rate held at 1,339.00. Despite the overall bearish sentiment, selective gains were seen in MLCC suppliers, quantum computing, and shipbuilding sectors.

SamwhaCapacitor (001820) +18.41%

SamwhaCapacitor surged 18.41% midday, driven by mounting market concerns over a potential supply shortage of Multi-Layer Ceramic Capacitors (MLCC) fueled by the rapidly growing artificial intelligence (AI) and energy storage system (ESS) sectors [5]. This supply anxiety sparked a broader rally among related MLCC stocks [6]. Although the stock experienced a 4.28% drop on September 8 [4] and intraday gains on September 9 [1][3], the exact drivers behind those earlier movements remain unconfirmed from the available headlines.

HD HYUNDAI HEAVY INDUSTRIES (329180) +6.28%

HD Hyundai Heavy Industries rose 6.28% following strong investor expectations surrounding its long-awaited engine capacity expansion and power generation engine orders surpassing $3.5 billion [8][10][12]. Anticipation for Small Modular Reactor (SMR) investments and the early establishment of an SMR manufacturing plant further boosted sentiment [11][12]. Analysts also highlighted that the stock remains significantly undervalued despite its massive 1 trillion KRW investment plan [8][9][10], helping the stock rebound from its 2.16% decline on September 10 [7].

AXGATE Co., Ltd. (356680) +29.94%

AXGATE reached its daily limit high, soaring 29.94% midday. The surge was primarily triggered by Nvidia CEO Jensen Huang identifying 'security' as the next core market for AI, which ignited a massive rally across information security themes [14][15]. Additionally, the company benefited from strong market interest in quantum computing stocks [16]. AXGATE also experienced upward momentum as part of a broader market trend where MLCC-related equities were rising sharply [17].

WOORIRO CO., LTD (046970) +13.73%

Wooriro climbed 13.73% midday, riding a wave of positive sentiment as a leading player in the quantum computing sector [21][22][24]. The stock has consistently attracted attention, posting intraday gains on September 10 [19][23] and hitting its upper limit on September 9 [20]. While the general sector strength has supported its upward trajectory, the specific micro-catalysts behind its September 9 limit-up remain unconfirmed from the provided headlines [20].

HankookCosmeticsManufacturing (003350) +19.98%

Hankook Cosmetics Manufacturing surged 19.98% midday, triggering two volatility interruption (VI) halts due to intense buying pressure [25]. The rally was heavily supported by strong supply-demand dynamics, featuring simultaneous net buying from both foreign and institutional investors [26]. Notably, institutional investors have maintained a net buying streak for five consecutive days [27]. However, the underlying business catalysts or specific corporate disclosures driving this sudden influx of capital remain unconfirmed from available headlines.

Sources

1. 삼화콘덴서 주가, 9월 9일 장중 116,700원 4.48% 상승 — 톱스타뉴스 · 2026-09-09
2. 삼화콘덴서 주가, 급등세... 왜? — 금강일보 · 2026-09-11
3. 삼화콘덴서 주가, 9월 9일 장중 117,400원 5.10% 상승 — 중앙이코노미뉴스 · 2026-09-09
4. 삼화콘덴서 주가, 9월 8일 111,700원 4.28% 하락 마감 — 톱스타뉴스 · 2026-09-08
5. [특징주] 삼화콘덴서, AI·ESS발 MLCC 공급 부족 우려에 19%대 급등 — 와이드경제 · 2026-09-11
6. MLCC 공급 부족 우려에…아모텍 상한가·삼화콘덴서 21%대↑ — 이코노뉴스 · 2026-09-11
7. HD현대중공업 주가, 9월 10일 453,500원 2.16% 하락 마감 — 톱스타뉴스 · 2026-09-10
8. [리포트 브리핑]HD현대중공업, '드디어 엔진 증설, 저평가된 주가 ' 목표가 860,000원 - iM증권 — 뉴스핌 · 2026-09-10
9. [애널픽] HD현대중공업, 1조 투자에도 주가 하락…"현저한 저평가" — 뷰어스 · 2026-09-11
10. 2026.09.11.(금) 증권사리포트 "HD현대중공업 - 드디어 엔진 증설, 저평가된 주가" — 네이버 프리미엄콘텐츠 · 2026-09-11
11. HD현대중공업, 엔진·SMR 투자 기대 5%↑…조선주 강세[핫종목] — 뉴스1 · 2026-09-11
12. [버핏 리포트] HD현대중공업, 발전 엔진 수주 35억 달러 돌파…SMR 공장 조기 구축 - 삼성 — 버핏연구소 · 2026-09-10
13. 엑스게이트 주가, 상한가... 왜? — 금강일보 · 2026-09-11
14. [ET특징주] 젠슨황 “AI 다음 핵심 시장은 '보안'”… 샌즈랩 · 엑스게이트 上 — 전자신문 · 2026-09-11
15. 특징주, 엑스게이트-정보보안 테마 상승세에 3.44% ↑ — 매일경제 마켓 · 2026-09-11
16. 우리로·우리넷·엑스게이트 등 양자컴퓨팅 관련주 강세 — gukjenews.com · 2026-09-09
17. [N2 증시 풍향계] MLCC 관련株 '들썩…엑스게이트·에스투더블유 급등, 진영은 상한가 — 뉴스투데이 · 2026-09-11
18. 엑스게이트 투자분석 2026. 09. 08 — 주달 · 2026-09-08
19. 우리로 주가, 9월 10일 장중 6,810원 3.65% 상승 — 톱스타뉴스 · 2026-09-10
20. 우리로 주가, 상한가... 왜? — 금강일보 · 2026-09-09
21. 양자컴퓨팅 관련주 장중 희비 우리로 4%대 상승 포톤도 강세 — CBC뉴스 · 2026-09-10
22. 우리로·우리넷·엑스게이트 등 양자컴퓨팅 관련주 강세 — gukjenews.com · 2026-09-09
23. 우리로 주가, 9월 10일 장중 6,750원 2.74% 상승 — 중앙이코노미뉴스 · 2026-09-10
24. 매출 절반이 하드디스크∙∙∙'양자 대장주' 우리로의 두 얼굴 — 리드경제 · 2026-09-09
25. [속보] 한국화장품제조 VI 두차례 발동, 주가 급등 — CBC뉴스 · 2026-09-11
26. [장중수급포착] 한국화장품제조, 외국인/기관 동시 순매수… 주가 +18.62% — 뉴스핌 · 2026-09-11
27. [장중수급포착] 한국화장품제조, 기관 5일 연속 순매수행진... 주가 +4.71% — 뉴스핌 · 2026-09-11
28. 한국화장품제조, 주주 타이거자산운용투자일임 측 주식등 보유 비율 5.28%p 감소 — 디지털투데이 · 2026-09-10

This is market commentary, not investment advice.