Oil breaks back above $100 as the U.S.-Iran war flares up again, dragging the KOSPI down to the 6,900s
🎧 Post Summary
📌 Post Summary
The KOSPI closed at 6,909.91 on September 11, down 124.01 points (1.76%) from the previous session, while the KOSDAQ fell 16.28 points (1.95%) to 820.64. Renewed fighting between the U.S. and Iran drove the sell-off, sending oil prices sharply higher. Brent crude jumped to $107.63 a barrel (+6.34%) and WTI to $102.48 (+6.69%), while the U.S. 10-year Treasury yield topped 4.95% intraday, its highest level since October 2023. Samsung Electronics fell 3.53% and SK Hynix 2.21%, both posting a second straight day of losses. Foreign and institutional investors sold heavily, while individual investors were the lone net buyers on the dip. Markets are now focused on tonight’s U.S. August CPI release (9:30 p.m. Korea time) and the Fed’s FOMC meeting on September 15-16.
The KOSPI, which had been holding just below the 7,000 mark, wobbled again. Renewed fighting between the U.S. and Iran in the Middle East sent oil prices decisively above $100 a barrel, while U.S. long-term Treasury yields spiked at the same time, weighing on markets both at home and abroad. Chip bellwethers Samsung Electronics and SK Hynix fell for a second straight day, reflecting the pullback in risk appetite. With tonight’s U.S. August Consumer Price Index (CPI) and next week’s Federal Open Market Committee (FOMC) meeting ahead, markets look more on edge than usual.
① KOSPI Slides Below 6,900 — How the Selloff Unfolded
The KOSPI closed at 6,909.91 on September 11, down 124.01 points (1.76%) from the previous session. Right after the open it plunged as much as 231.42 points (3.29%) to 6,802.50, showing sharp volatility throughout the day. The KOSDAQ also fell 16.28 points (1.95%) to 820.64. Foreign investors net-sold 2.3041 trillion won and institutions net-sold 1.2235 trillion won, while individual investors were the lone net buyers at 1.8658 trillion won, cushioning the decline. By sector, electronics, manufacturing, and precision instruments fell more than 2%, while construction, insurance, real estate, general services, and utilities actually gained around 1%. The fact that the day was also a quadruple witching day (simultaneous expiration of futures and options) added to the intraday volatility.
② A Middle East Oil Shock — What’s Behind Oil’s Return Above $100
The epicenter of this selloff is the Middle East. The U.S.-Iran military conflict, which has dragged on for more than six months, flared up again recently: after the U.S. military struck tankers linked to Iran’s Revolutionary Guard Corps, Iran retaliated with ballistic missile strikes on a U.S. base. Traffic through the Strait of Hormuz reportedly plunged from roughly 8 million barrels a day in the last week of August to about 1 million barrels a day this week. Adding to the supply concerns, pro-Iran Houthi rebels struck energy facilities in Saudi Arabia. As a result, Brent crude closed at $107.63 a barrel (+6.34%) and WTI at $102.48 (+6.69%) on September 11. Major investment banks including Goldman Sachs warned that if the conflict drags on, oil could climb to $120-150 a barrel in the fourth quarter.
③ U.S. Treasury Yields at 4.95% — Chip Stocks Fall in Tandem
The oil spike also pushed up U.S. Treasury yields. The 10-year yield topped 4.95% intraday, its highest level since October 2023. Rate-sensitive tech stocks led the selling, dragging all three major Wall Street indexes lower for a fourth straight session, while the Philadelphia Semiconductor Index fell 2.66%. Nvidia (-2.26%), Micron (-4.90%), and Intel (down roughly 6%) all posted sharp losses. The spillover hit Korean chipmakers too: Samsung Electronics fell 3.53% to close at 259,500 won, and SK Hynix fell 2.21% to 1,812,000 won on September 11. It was Samsung’s second consecutive day of declines. Samsung and SK Hynix also topped the list of stocks institutions net-sold the most.
④ The Next Catalysts: U.S. CPI and the FOMC
Markets are now looking ahead to tonight’s U.S. August Consumer Price Index (CPI), due at 9:30 p.m. Korea time (8:30 a.m. U.S. Eastern time). The market consensus calls for headline CPI to rise 0.4% month-over-month and core CPI to rise 0.2%. This CPI print is effectively the last major data point before the Fed’s FOMC meeting on September 15-16. With strong recent employment data now compounded by the oil spike, the market-implied odds of a rate hike have climbed to an unusual 55-60% range. The Bank of Korea has already raised its own policy rate to 3.00% on August 27, raising concerns that domestic inflation and rate pressures could intensify further.
⑤ A Domestic Policy Variable — Whether to Extend the Fuel Tax Cut
At home, attention is turning to whether the government will extend its fuel tax cuts (15% on gasoline, 25% on diesel), which are set to expire on September 30. The government has been running a price cap on oil products to keep the recent price spike from being passed straight through to consumers, but it now faces a dilemma: freezing the cap means a growing fiscal burden to compensate refiners for losses, while raising it would add to the cost-of-living pressure on ordinary households just ahead of the Chuseok holiday travel rush. This latest oil price surge hasn’t yet shown up in inflation data, and the Bank of Korea and other analysts expect it to appear mainly in the petroleum component of the September and October CPI reports.
📌 Key Takeaways for Investors
- In a period of heightened short-term volatility, a phased approach may be safer than aggressive leverage or short-term trading.
- Rising oil prices could be a relative tailwind for sectors like refining, shipbuilding, and defense, so it’s worth watching how different sectors respond.
- Volatility could widen further heading into major events like the CPI release and the FOMC meeting.
- Geopolitical risk is inherently hard to forecast, so it’s advisable to focus on risk management rather than betting on a specific scenario.
With an escalating Middle East war, a surge in oil prices, and jitters over U.S. interest rates all colliding at once, Korean equities have slipped back below the 7,000 level. The key catalysts now are tonight’s CPI print and next week’s FOMC meeting. If inflation comes in hotter than expected, the odds of a Fed rate hike would rise further, adding pressure on both Korean equities and the won. Conversely, if CPI meets or falls short of expectations, investor sentiment could stabilize somewhat. With volatile trading likely to continue heading into the Chuseok holiday, it looks worth preparing event-specific response strategies in advance.
References
- Money Today (mt.co.kr) — “KOSPI Slips Below 7,000 for the First Time in Three Days… Attention Now Turns to the FOMC”
- Segye Ilbo (segye.com) — “Samsung and SK Hynix Fall 2-3% Amid U.S. Tech Rout… Top Two Foreign/Institutional Net Sells”
- Businesskorea (businesskorea.co.kr) — “[Market Close] KOSPI Falls Below 7,000 to Close at 6,909.91”
- Asia Economy (asiae.co.kr) — “Chip Exports Hit Another Record This Month, Up 270% to $16.5 Billion”
- Hankyung (hankyung.com) — “U.S. August CPI to Decide September Rate Call… 0.1 Point Could Mean Hike vs. Hold”
- Seoul Ilbo (seoulilbo.co.kr) — “Oil Back Above $100 Again… How Long Can the Price Cap ‘Shield’ Hold?”
- Sankyung Today (sankyungtoday.com) — “Rate and Oil Shock Send Samsung, SK Hynix Tumbling… Foreign Selling Concentrated”