Seoul Stocks: KOSPI and KOSDAQ Daily — 2026-09-13
The KOSPI closed below the psychological 7,000-point threshold on Friday, September 11, as geopolitical tensions in the Middle East drove oil prices higher and global bond yields surged. Despite a strong start to the week driven by semiconductor optimism, retail investors turned net sellers for the first time in five months, dumping 13 trillion won worth of Samsung Electronics and SK hynix shares.
Seoul Stocks: KOSPI and KOSDAQ Daily — 2026-09-13
Top developments
KOSPI breaks below 7,000 amid geopolitical and rate fears
The benchmark KOSPI fell 1.76% on Friday, September 11, closing at approximately 6,910 points, marking its first close below 7,000 in months. The decline was triggered by overnight losses on Wall Street following Houthi strikes on Saudi energy facilities, which pushed Brent crude above $107 and heightened inflation concerns. Consequently, Federal Reserve rate-hike odds rose to nearly 90% ahead of the upcoming FOMC meeting, weighing heavily on risk assets across Asia.

Retail investors shift to net sellers for chip giants
Individual investors ("ants") have reversed their long-standing buying trend, selling a net 13 trillion won worth of Samsung Electronics and SK hynix shares since the beginning of September. This marks the first time in five months that retail traders have been net sellers of these key semiconductor stocks, signaling a loss of confidence or profit-taking after the earlier rally. The shift occurred despite foreign and institutional buying earlier in the week, leaving the market without a clear dominant buyer on Friday.

Semiconductor volatility: AI optimism vs. DeepSeek threat
The week saw extreme volatility in chip stocks. On Monday, September 7, the KOSPI jumped nearly 5% to near 7,000 points as OpenAI’s GPT-6 release sparked renewed AI spending optimism, lifting Samsung and SK hynix. However, by Friday, shares dipped again after reports that DeepSeek’s new AI technology could reduce memory demand, raising questions about the sustainability of the AI-driven chip boom. This whiplash effect contributed to the broader market's inability to sustain gains above 7,000.

Local view
Financial News (fnnews) reported that on Friday, the KOSPI closed at the 6,900 level after being dragged down by foreign and institutional selling. They noted that large-cap semiconductor stocks dropped over 3% due to deteriorating sentiment caused by the US-Iran conflict escalation.
Yonhap News Agency highlighted that while foreign investors had been buying chip stocks early in the week, the momentum stalled as domestic retailers began exiting positions. Yonhap emphasized that the "ant" (retail) investor exodus from Samsung and SK hynix is a critical signal for market stability in the short term.
Context & numbers
- KOSPI Close (Sept 11): ~6,910 points (down 1.76% from previous session).
- Retail Net Selling (Sept MTD): 13 trillion won in Samsung Electronics and SK hynix.
- Oil Prices: Brent crude topped $107 following Middle East tensions.
- Foreign Flows: Foreign and institutional investors were net buyers on Monday (Sept 7) but turned net sellers by Friday (Sept 11).

On the radar
- FOMC Meeting: Investors are watching the upcoming US Federal Reserve meeting closely, with rate hike odds near 90%, which will dictate global liquidity and won-dollar exchange rates.
- Value-Up Programme: With 756 firms now disclosing Value-Up plans (covering 87.7% of KOSPI value), attention shifts to whether these disclosures can reignite domestic institutional interest if foreign flows remain volatile.
- DeepSeek Impact: Continued analysis of DeepSeek’s memory-efficient AI models may further pressure SK hynix and Samsung Electronics valuations if demand forecasts are revised downward.
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