All 3 Major U.S. Stock Indexes Fall for a Third Straight Day as Brent Crude Breaks Above 100 Dollars
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As of the morning of 2026-09-10 Korea time, the latest confirmed regular-session results on Wall Street showed not gains but declines across all 3 major indexes. In the U.S. session on September 9, the Dow fell 0.77%, the S&P500 declined 0.48%, and the Nasdaq lost 0.64%. Brent crude also exceeded 100 dollars per barrel that day.
As tensions between the United States and Iran continued, rising oil prices and U.S. Treasury yields added to the pressure facing financial markets. However, not every stock moved in the same direction. Energy shares and some technology stocks performed differently from the broader indexes.
How Much Did Wall Street Actually Fall on September 9?
At the latest close, the Dow Jones 30 Industrial Average finished at 52,380.66, the S&P500 closed at 7,636.36, and the Nasdaq Composite ended at 26,253.34. Their respective declines from the previous session were 0.77%, 0.48%, and 0.64%.
The declines for each index were as follows.
Dow Jones 30: Down 405.41 points, -0.77%
S&P500: Down 37.16 points, -0.48%
Nasdaq: Down 168.07 points, -0.64%
All three indexes had declined for 3 consecutive trading sessions through that day.
Therefore, describing the current market as 'Wall Street rises despite tensions with Iran' would be inconsistent with the latest confirmed results. Intraday movements, futures indexes, and developments from previous trading sessions must be distinguished from official regular-session closing figures.
This distinction is particularly important for investors in Korea, who may encounter U.S. market news in the morning and easily confuse 'rising futures' with 'the previous day's regular-session close.' As of the morning of September 10, the latest confirmed regular-session results were the declines recorded in the U.S. session on September 9.
Why Brent Crude at 100 Dollars Matters to the Stock Market
On September 9, Brent crude closed at 101.21 dollars per barrel, crossing the 100-dollar threshold for the first time since July. West Texas Intermediate (WTI) crude closed at 96.05 dollars per barrel.
Rather than concluding that stocks moved solely because of 'war news,' it is more accurate to examine the market factors observed that day together. International oil prices and U.S. Treasury yields both rose, placing additional pressure on Wall Street.
When oil prices rise, energy costs for businesses and consumers can also increase. Investors consequently assess how elevated oil prices might affect inflation trends and expectations for interest rates.
On the same day, the yield on the 10-year U.S. Treasury exceeded 4.85% during trading, reaching its highest level since November 2023. This explains why equity investors should monitor Treasury yields alongside oil prices.
What Has Actually Been Confirmed Between the United States and Iran?
U.S. Central Command stated on September 8 that Iran's Islamic Revolutionary Guard Corps had attempted to attack U.S. Navy vessels twice with ballistic missiles over the preceding two days. According to the U.S. military, the targeted American vessels avoided the attacks, and no U.S. personnel were injured or killed.
In response, U.S. Central Command announced on September 8 that it had destroyed 5 Iranian oil tankers. Its announcement identified Kaviz, Charminar, Horizon 1, and Riesco in the Gulf of Oman, along with Derya near Kharg Island.
An important distinction is necessary here. The statements from U.S. Central Command constitute information officially released by the U.S. military. However, that does not mean every claim made by the parties involved in the fighting has been independently verified to the same standard. Unconfirmed outcomes of attacks should not be presented as established facts.
For the stock market, the key issue is not predicting military developments themselves but determining whether actual crude oil supplies and transportation conditions are changing.
Why Did Energy Stocks Rise While the Major Indexes Fell?
Although the overall S&P500 index declined 0.48%, the S&P500 energy sector index rose 1.1%. Every other S&P500 sector index declined that day.
This movement illustrates how different industries can respond differently to changes in international oil prices, even within the same U.S. stock market.
Higher energy prices can increase costs for the broader economy while creating different conditions for companies that produce oil and natural gas. In the September 9 session, the energy sector was the only sector to rise against the direction of the overall index.
Technology stocks did not all move together either. Meta gained more than 6%, and AMD rose 3%. Meanwhile, Alphabet declined 2.3%, and Apple fell 0.3%.
Simplifying the situation as 'Nasdaq down means all technology stocks fell' or 'war risks mean every stock weakens' overlooks the differences that emerged within the market that day.
What Does Comparing This Decline With Previous Trading Sessions Reveal?
All 3 major U.S. stock indexes also declined on September 8. At that time, the S&P500 fell 0.6%, the Dow declined 1.2%, and the Nasdaq lost 0.3%.
On September 9, the Dow recorded -0.77%, the S&P500 posted -0.48%, and the Nasdaq registered -0.64%.
A straightforward comparison of the two sessions shows that the daily percentage declines in the Dow and S&P500 moderated somewhat on September 9, while the Nasdaq's decline became larger than the previous day's. However, this comparison alone is insufficient to conclude that the market's direction has changed.
At the close on September 9, the S&P500 was approximately 2% below its record closing high set on August 13. At the same time, it remained approximately 12% higher since the beginning of 2026.
In other words, the declines of the past several days and the performance since the beginning of the year represent different time frames. Investors need to distinguish between 'weakness over the latest 3 trading sessions' and 'cumulative gains in 2026' to understand the market's current position accurately.
What Should Investors Check First in the Next Wall Street Session?
The first figure to watch is the international oil price. As of the morning of September 10 Korea time, Brent crude was still trading in the 101-dollar range, remaining above 100 dollars.
The second factor is U.S. Treasury yields. On September 9, the yield on the 10-year Treasury exceeded 4.85% during trading. Market conditions could change depending on whether oil prices and Treasury yields remain elevated together or whether one of them reverses direction.
The third factor is U.S. inflation data. Investors are awaiting the Producer Price Index scheduled for release on September 10 and the consumer inflation figures scheduled for September 11. Because the actual figures have not yet been confirmed, their results cannot be predicted with certainty at this stage.
Finally, investors should examine sector performance rather than focusing only on headline indexes. As demonstrated on September 9, the energy sector can rise even when the overall S&P500 falls, and substantial differences can emerge among individual technology stocks.
What Korean Investors Should Keep in Mind About This Wall Street Decline
The actual closing performance does not support describing this market simply as 'U.S. stocks held up despite tensions with Iran.' During the regular session on September 9, the Dow, S&P500, and Nasdaq all declined while oil prices exceeded 100 dollars.
Conversely, saying that 'all stocks fell because of the war' would also be inaccurate. The S&P500 energy sector rose, while some technology companies, including Meta and AMD, gained on company-specific developments.
For an easier comparison of market changes in the next session, investors can follow this sequence: Dow, S&P500, and Nasdaq closing levels → Brent crude → U.S. 10-year Treasury yield → inflation indicators → sector-by-sector performance.
As of the morning of September 10 Korea time, the results of the next U.S. regular trading session had not yet been finalized. Intraday gains or losses in futures indexes may differ from the actual regular-session closing figures. Therefore, whether 'Wall Street rose' should be verified again using the final closing levels of the 3 major indexes after trading ends.
When making investment decisions, it is important not to assume a market direction based solely on one day's geopolitical news or index movements. Oil prices, interest rates, inflation indicators, and the circumstances of individual companies should all be considered. Stock and commodity prices can change rapidly in response to subsequent news and economic data.
※ This article is provided for informational purposes to help readers understand market developments and does not constitute an investment recommendation for any specific stock or asset. All final investment decisions and responsibilities rest with the individual investor.
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이 포스팅은 쿠팡 파트너스 활동의 일환으로, 이에 따른 일정액의 수수료를 제공받습니다.