Dow Falls 1.18% While Nasdaq Drops 0.32%: Why the Same Oil Price Shock Hit Them Differently
In the U.S. stock market on 2026-09-08, the Dow fell 1.18%, while the Nasdaq declined just 0.32%. Although both faced the same surge in oil prices and tensions in the Middle East, the main reasons for the difference were the Dow's price-weighted structure and sharp declines in high-priced components such as Amgen, along with gains in some semiconductor stocks that helped limit the Nasdaq's losses.
The Dow Fell Approximately 3.7 Times as Much as the Nasdaq
Based on the closing prices on September 8, the S&P500 fell 0.58%, the Nasdaq Composite declined 0.32%, and the Dow Jones Industrial Average dropped 1.18%.
A simple comparison shows that the difference between the Dow's and Nasdaq's percentage declines was 0.86% points.
Author's calculation
Dow decline: 1.18%
Nasdaq decline: 0.32%
Ratio of declines: 1.18 ÷ 0.32 ≈ 3.69 times
Therefore, interpreting the session simply as a day when rising oil prices caused all U.S. stock indexes to fall by similar amounts would overlook what actually happened in the market.
Higher oil prices weighed on the broader market, but the influence of individual stocks within each index determined the extent of their respective declines.
Why Can Just One or Two Stocks Have Such a Large Impact on the Dow?
The Dow is a price-weighted index that assigns greater weight to stocks with higher share prices, rather than weighting companies by market capitalization.
Put simply, a company with a larger market capitalization does not necessarily have a greater influence on the Dow. If a component with a high share price falls sharply, the Dow can move more than investors might expect.
Amgen was a prime example on September 8.
Early in the trading session, Amgen shares plunged approximately 6%. The decline alone was calculated to have dragged Dow futures down by roughly 158 points at the time. This reflected Amgen's relatively high share price among Dow components.
Amgen's weakness followed disappointing late-stage clinical trial results for a cardiovascular treatment developed by Swiss pharmaceutical company Novartis. Those results raised concerns about Amgen, which is developing treatments in a similar area.
In other words, the Dow's decline that day reflected not only international oil prices but also a separate factor: a sharp drop in an individual major index component.
Why Was the Nasdaq's Decline Smaller?
Not all technology stocks performed well on the Nasdaq, either.
Software stocks were weak, with Salesforce and Intuit falling approximately 4% and ServiceNow declining 5%. However, Intel gained 9% and Qualcomm rose 3.2%, partially offsetting the index's losses.
The strength of certain semiconductor and AI infrastructure stocks was particularly important.
Therefore, rather than interpreting the Nasdaq's 0.32% decline as evidence that it was barely affected by the oil price shock, it is more accurate to say that weakness in some sectors was offset by strength in others, limiting the overall index decline.
On the same day, declining stocks outnumbered advancing stocks in the S&P500 by a factor of 2.4, yet the energy sector gained 1%. This indicates that the market was not moving uniformly in one direction.
Why Can Energy Stocks Rise When Oil Prices Increase?
Rising oil prices can increase inflationary and interest-rate pressures on the broader stock market, but they are not necessarily bad news for every company.
Companies that produce or refine crude oil may benefit from higher selling prices, potentially improving their earnings. Conversely, transportation, airline, and industrial companies that consume large amounts of fuel, as well as businesses that cannot immediately pass higher energy costs on to customers, may face greater cost pressures.
On September 8, the S&P500 energy sector gained 1%, while Marathon Petroleum rose 2.4% and Occidental Petroleum advanced 1%.
Therefore, instead of relying on the simplistic formula that 'higher oil prices = lower stock prices across the board,' investors should consider two simultaneous effects: rising oil prices → greater inflation and interest-rate pressures + different profit impacts across sectors.
What to Watch in the Next Trading Session: Look Inside the Indexes, Not Just at Their Levels
Comparing only the percentage changes in the Dow and Nasdaq can lead to a misleading interpretation of the U.S. stock market.
In particular, an index such as the Dow, which has relatively few components and uses price weighting, can be significantly affected by sharp movements in individual high-priced stocks. Meanwhile, within the Nasdaq, semiconductor companies, software firms, and internet platforms can move in different directions.
When analyzing the market on September 8, it is useful to examine four factors separately.
Whether oil prices continue to rise
Whether U.S. Treasury yields rise at the same time
Whether the performance gap widens between energy stocks and energy-consuming industries
Which Dow components are actually responsible for the index's point losses
Especially on days when the Dow falls much more sharply than the Nasdaq, as it did in this session, asking 'Which stocks are actually dragging down the Dow?' is more useful for interpreting the index than simply asking 'Why is the entire U.S. stock market so weak?'
Stock index movements reflect the combined effects of individual companies, sectors, interest rates, and commodity prices. Rather than drawing firm conclusions about future market direction from a single day's percentage changes, investors should also examine the underlying factors driving each index.
※ This article is provided for informational purposes to help readers understand market trends and does not constitute investment advice or a recommendation to buy or sell any particular security or asset. All investment decisions and their associated risks remain the responsibility of the individual investor.