The Easy Knowledge Blog

Oil breaks $90 and Wall Street slides after Iran’s second strike, but KOSPI rallies on shaky footing

📌 Post Summary

The US-Iran conflict, which had been relatively quiet for nearly a month, flared up again this week. Following the first strike on a rocket launch site on Larak Island in the Strait of Hormuz on August 30, the US carried out a second attack on Iranian Revolutionary Guard Corps (IRGC)-linked targets on September 1 (local time), pushing markets past mere risk-watching and into real asset losses. Oil, bond yields, Wall Street, and crypto all wobbled like dominoes over the course of the day — except for KOSPI, which moved in the opposite direction and caught everyone’s attention. Here’s what happened, and whether that rebound should be taken at face value.

① A Second Strike, 24 Hours Later

US Central Command (CENTCOM) said it launched a new strike on IRGC-linked targets on September 1 (local time), describing it as a response to recent IRGC attempts to target merchant vessels transiting the Strait of Hormuz and deployed US personnel. President Donald Trump framed the strike as retaliation for Iran’s attempt to mine the Strait of Hormuz and its attack on a US base in Jordan, warning that further US strikes could follow if Iran retaliates again. Iran’s military said it had launched a “decisive operation” in response, according to semi-official Tasnim news agency, while an IRGC spokesperson told Fars news agency that “the US will come to regret this new attack.”

② Oil Breaks $90, Bond Yields Hit a 19-Month High

Following the first strike, WTI crude closed regular trading on September 1 up 2.83% at $85.76 a barrel, while Brent rose 2.71% to $90.49. After news of the second strike broke, WTI futures pushed back above $90 for the first time since late July. The oil spike stoked fresh inflation concerns, and the US 10-year Treasury yield climbed as high as 4.798% intraday — its highest level since January of last year. According to CME FedWatch, market pricing for a September Fed rate move has also shifted higher.

③ Wall Street Opens September in the Red

Weighed down by both oil and rate pressures, all three major Wall Street indexes closed lower on the first trading day of September. The Dow Jones Industrial Average fell 419.02 points (0.79%) to 52,766.88, the S&P 500 dropped 54.67 points (0.71%) to 7,631.47, and the tech-heavy Nasdaq Composite lost 271.12 points (1.03%) to close at 26,099.77. The rate-sensitive small-cap Russell 2000 also slid more than 1%.

④ Why Did KOSPI Rally Alone? A Look at the Numbers Behind a ‘Hollow Rebound’

KOSPI moved in the opposite direction despite facing the same risk backdrop. The index fell as much as 1.28% intraday to 6,732.47 on September 1 before fully recovering its losses to close up 0.23% at 6,835.80. Large-cap semiconductor names like SK hynix and Samsung Electronics led the recovery. But the underlying flows tell a different story: foreign investors sold a net 491.9 billion won, institutions sold 634.0 billion won, retail investors sold 539.8 billion won, and program trading sold 320.3 billion won. All four major participant groups were net sellers, yet the index still rose — a pattern that suggests buying from other corporate entities and treasury-share purchases, along with price support in select large caps, propped up the index. KOSDAQ, by contrast, fell 1.56% (13.04 points) to close at 821.25, a notably different tone from KOSPI. Whether trading volume and foreign/institutional flows actually turn positive in the next session will be the real test of this rebound.

⑤ Bitcoin and Crypto Markets Pull Back Too

Risk-off sentiment spilled over into crypto markets as well. Bitcoin fell 2.10% over 24 hours to $77,348.26, while major altcoins like Ethereum (-2.54%) and Solana (-3.99%) fell even more sharply. In derivatives markets, long positions betting on further gains were liquidated, but spot ETFs still saw over $300 million in net inflows, suggesting the broader market didn’t tip into panic selling. CoinMarketCap’s Fear & Greed Index still reads 72, in “Greed” territory, indicating medium-term bullish sentiment hasn’t broken down.

📌 Things Worth Keeping in Mind

• Middle East geopolitical risk can filter through to domestic prices and the exchange rate via oil, so it’s worth keeping a close eye on oil market headlines.
• Both the US and Iran keep signaling they don’t want a full-scale war, so it helps to separate short-term volatility from the longer-term risk of broader conflict.
• KOSPI’s gain may reflect a ‘flow illusion’ without genuine buying support, so watch whether trading volume and foreign/institutional flows actually turn positive in the next session.
• The Fed’s rate decision direction in September could shift depending on how oil prices and geopolitical risk evolve, so it’s worth preparing for further volatility in Korean equities.

The US-Iran standoff has broken out of a month-long lull and is escalating again. Still, with both sides signaling they don’t want an all-out war, whether further retaliation follows and how shipping through the Strait of Hormuz holds up in the coming days will be the key variables shaping the next move in oil prices and equity markets at home and abroad.

References

• ETODAY – “US Strikes Iran Again, WTI Breaks $90 as Hormuz Tensions Reignite” (etoday.co.kr)
• ETODAY – “[Breaking] Wall Street Closes Lower on Middle East Tension, Bond Selloff — Nasdaq Down 1.03%” (etoday.co.kr)
• Edaily – “Oil at $90, US Treasury Yield at 4.8% ‘Double Pressure’ — Nasdaq Down 1% [Wall Street In]” (edaily.co.kr)
• Blockmedia – “[Wall Street Close] Stocks Fall Across the Board as US-Iran Conflict Reignites — Nasdaq Down 1.03%” (blockmedia.co.kr)
• Blockmedia – “[NY Crypto Close] Coins Weaken on Middle East Risk, High Rates — Bitcoin Retreats to $77K” (blockmedia.co.kr)
• CBC News – “[Breaking] Wall Street Falls Across the Board on First Trading Day of September — Nasdaq Down 1.03%” (cbci.co.kr)
• Peter Lee (X) – “September 1, 2026 Korean Stock Market Closing Briefing” (x.com)