KOSPI and KOSDAQ rally on AI data‑centre demand and US curbs on Chinese optical transceivers

The KOSPI closed at 6,299.66, up 0.65%, while the KOSDAQ surged 6.97% to 854.47, reflecting broad optimism in high‑tech and construction sectors. The won weakened to 1,412.20 per dollar and foreign investors recorded a net sell of KRW 1.49 bn on the KOSPI but a net buy of KRW 0.10 bn on the KOSDAQ. The market tone was upbeat, driven by expectations of AI data‑centre growth and anticipated benefits from U.S. restrictions on Chinese optical transceivers.

TAIHAN Fiberoptics Co.,LTD (010170) +22.51%

TAIHAN Fiberoptics Co.,LTD chart

Price now₩14,040
Prev close₩11,460
Change+22.51%
Mkt cap₩2.2T
P/E-58.02
P/B28.59
EPS₩-242
ROE-28.75%
Debt ratio116.70%
52W range₩923–31,500

TAIHAN Fiberoptics leapt 22.51% after a wave of buying sparked by two catalysts. First, U.S. authorities announced plans to restrict Chinese‑made optical transceivers, prompting investors to view Korean optical firms as beneficiaries; this was highlighted in reports of a 17% surge and the “reflection benefit” narrative [5][3]. Second, momentum from AI data‑centre orders added further optimism, as noted in a pre‑market analysis on August 9 [6]. An early‑session price jump was also reported by CBC News [1].

GS Engineering & Construction Corp (006360) +10.27%

GS Engineering & Construction Corp chart

Price now₩34,900
Prev close₩31,650
Change+10.27%
Mkt cap₩3.0T
P/E31.93
P/B0.62
EPS₩1,093
ROE1.40%
Debt ratio231.27%
52W range₩17,790–44,850

Analyst consensus — 19 ratings, last 180 days · avg target ₩38,158

Buy19
Hold0
Sell0

GS Engineering & Construction rose 10.27% after securities houses upgraded their outlook, citing an “intersection of construction‑sector investment strategies” and raising the target price to KRW 43,000 [7][10]. The upgrade was reinforced by growing expectations for AI data‑centre construction, which could boost the company's order book [8]. Market reaction was evident with an 8.53% intraday gain reported on August 10 [9]. The combined analyst optimism and sector‑specific demand fueled the rally.

LIG Defense&Aerospace (079550) +11.07%

LIG Defense&Aerospace chart

Price now₩823,000
Prev close₩741,000
Change+11.07%
Mkt cap₩18.1T
P/E71.47
P/B12.57
EPS₩11,516
ROE22.47%
Debt ratio440.12%
52W range₩360,000–1,118,000

LIG Defense&Aerospace surged 11.07% on August 10 after analysts lifted their price targets to KRW 1.2‑1.3 million, citing rising export volumes and year‑on‑year earnings growth [14][16]. The “130만원 간다” forecast and positive commentary from the analyst firm Cheon‑Gung further amplified buying pressure [11][12]. Although the stock experienced a brief post‑earnings dip, the overall sentiment remained bullish as investors focused on the longer‑term growth narrative [13].

AUK (017900) +14.08%

AUK chart

Price now₩8,910
Prev close₩7,810
Change+14.08%
Mkt cap₩516B
P/E122.05
P/B1.86
EPS₩73
ROE2.51%
Debt ratio8.52%
52W range₩1,760–22,450

AUK jumped 14.08% amid a sector‑wide rally in optical‑communication and photonics stocks. Analysts highlighted expanding AI data‑centre demand and a strategic shift from copper to light‑based transmission, which should benefit firms like AUK [18]. The rally was reinforced by news of U.S. moves to curb Chinese optical transceivers, giving Korean players a competitive edge [20]. Broader sector momentum, including multiple “VI” triggers, further propelled buying [19][21].

DaewonCable (006340) +8.41%

DaewonCable chart

Price now₩14,950
Prev close₩13,790
Change+8.41%
Mkt cap₩1.2T
P/E132.3
P/B9.79
EPS₩113
ROE9.86%
Debt ratio120.57%
52W range₩2,765–20,300

DaewonCable advanced 8.41% as investors priced in potential upside from AI data‑centre projects and a KRW 83 trillion power‑grid expansion, both cited as key growth drivers [23]. The stock also benefited from the overall market strength, with the KOSPI and KOSDAQ posting solid gains on the day [24]. Intraday data showed a 5.22% rise, confirming the positive sentiment toward infrastructure‑linked equities [25].

Sources

  1. [속보] 대한광통신 VI 발동, 주가 장초반부터 급등...양대지수도 '맑음' — CBC뉴스 · 2026-08-10
  2. 대한광통신 주가, 급등세... 왜? — 금강일보 · 2026-08-10
  3. 대한광통신·광전자 등 급등…美 중국산 광트랜시버 규제 추진 — econonews.co.kr · 2026-08-10
  4. 대한광통신 주가, 8월 7일 장중 11,410원 3.07% 상승 — 톱스타뉴스 · 2026-08-07
  5. [특징주] 대한광통신, “美 중국산 광트랜시버 금지 추진” 반사수혜 기대감에 ‘17% 급등’ — 와이드경제 · 2026-08-10
  6. 대한광통신, 월요일 앞두고 AI데이터센터 수주 모멘텀 재점검 — CBC뉴스 · 2026-08-09
  7. GS건설 '현 시점 건설업종 투자전략의 교집합' 증권사 발표에 강세…9.64% — 매일경제 마켓 · 2026-08-10
  8. AI 데이터센터 가동 기대감에 GS건설 주가 '상승' — gukjenews.com · 2026-08-10
  9. GS건설 주가, 8월 10일 장중 34,350원 8.53% 상승 — 톱스타뉴스 · 2026-08-10
  10. [리포트 브리핑]GS건설, '현 시점 건설업종 투자전략의 교집합' 목표가 43,000원 - KB증권 — 뉴스핌 · 2026-08-10
  11. [특징주] LIG디펜스앤에어로스페이스, 천궁 긍정 분석.. '급등' — 글로벌이코노믹 · 2026-08-10
  12. "LIG디펜스앤에어로스페이스, 130만원 간다" 증권가 전망에 급등 - 머니투데이 — 머니투데이 · 2026-08-10
  13. LIG디펜스앤에어로스페이스, 실적 발표 후 급락→반등⋯증권가 “28년까지 튼튼” — 이투데이 · 2026-08-07
  14. [리포트 브리핑]LIG디펜스앤에어로스페이스, '수출 증가로 전년비 실적 증가세 지속' 목표가 1,300,000원 - LS증권 — 뉴스핌 · 2026-08-07
  15. LIG디펜스앤에어로스페이스 주가, 8월 10일 장중 813,000원 9.72% 상승 — 톱스타뉴스 · 2026-08-10
  16. [리포트 브리핑]LIG디펜스앤에어로스페이스, '실적과 수주, 길게 보면 폭발적 성장' 목표가 1,200,000원 - 유진투자증권 — 뉴스핌 · 2026-08-07
  17. 광전자 주가, 8월 7일 장중 7,950원 17.08% 상승 — 톱스타뉴스 · 2026-08-07
  18. 대한광통신·광전자 동반 주가 급등…AI 데이터센터 ‘구리에서 빛으로’ 광통신·광반도체주 들썩 — CBC뉴스 · 2026-08-10
  19. [서울데이터랩]코스피 거래상위 종목 혼조…혜인 26% 급등, 한화솔루션·광전자 강세 — twig24.com · 2026-08-07
  20. 대한광통신·광전자 등 급등…美 중국산 광트랜시버 규제 추진 — econonews.co.kr · 2026-08-10
  21. 광전자 주가 급등흐름…오전 VI 2회 발동되기도 — CBC뉴스 · 2026-08-07
  22. 광전자 주가, 8월 10일 장중 9,220원 18.05% 상승 — 톱스타뉴스 · 2026-08-10
  23. 대원전선 주가 전망 2026｜AI 데이터센터·83조 전력망 수혜, 목표가와 매수 전략 — 네이버 프리미엄콘텐츠 · 2026-08-10
  24. 대원전선 주가, 연속 약세 딛고 주초장 8%대 강세 마감…코스피·코스닥도 상승 — CBC뉴스 · 2026-08-10
  25. 대원전선 주가, 8월 10일 장중 14,510원 5.22% 상승 — 톱스타뉴스 · 2026-08-10
  26. 대원전선우 투자분석 2026. 08. 06 — 주달 · 2026-08-06

This is market commentary, not investment advice.