U.S. Stocks Fall as Iran Tensions Drive Oil and Bond Yields Higher

U.S. stocks fell on September 28 as tensions with Iran drove crude oil prices and Treasury yields sharply higher, intensifying concerns over inflation and Federal Reserve rate hikes. The S&P 500 dropped 0.77%, the Dow fell 0.67%, and the Nasdaq declined 0.92%, with rising energy costs pressuring airlines and other fuel-intensive sectors.

Quick Facts

U.S. stock market declined
Oil prices spiked above $100 per barrel then retreated
Treasury bond yields surged to highest levels in nearly 19-20 years
Trump rejected Iran's proposal to reopen Strait of Hormuz
Brent crude rose 0.92% to above $105 per barrel

U.S. stock markets declined on September 28 as escalating tensions with Iran sent crude oil prices and Treasury bond yields surging, intensifying investor concerns over inflation and monetary policy. The S&P 500 fell 0.77%, the Dow Jones dropped 0.67%, and the Nasdaq Composite declined 0.92%, with eight of eleven primary sectors ending in the red. Communication services and consumer discretionary led declines, while consumer staples and healthcare posted modest gains.

Oil price volatility underpinned the market selloff. Brent crude initially spiked above $100 per barrel before retreating, while West Texas Intermediate crude ended near $92.60 after reaching $96.54 during the session. The price swings followed President Donald Trump's rejection of Iran's proposal to reopen the Strait of Hormuz and resume nuclear negotiations. Mediators continued working toward a deal to end the conflict and restore shipping through the strategic waterway, which had been disrupted since a February U.S.-Israel military operation against Iran.

Treasury yields extended their climb, with the 10-year yield jumping to 5.25%—its highest level since mid-2007 and the highest in nearly nineteen years. The 30-year yield approached 5.6%, matching 2004 levels, while the two-year yield rose above 4.9%. Rising bond yields made borrowing more expensive and pressured stock valuations, particularly in rate-sensitive sectors. Oil price increases also weighed on airlines and energy-intensive companies; American Airlines fell 2.4% and United Airlines dropped 1.8%. Gold miners weakened as rising yields reduced gold's appeal as an inflation hedge, with Newmont declining 4.2%.

Market strategists attributed the downturn to overlapping concerns. Rising energy costs risked fueling inflation, prompting expectations of additional Federal Reserve rate hikes. Traders priced in approximately a 70% probability of another quarter-point rate hike at the Fed's October 28 meeting, following the central bank's first increase since 2023 in September. Gasoline prices had risen to nearly $4.48 per gallon from $3.13 a year earlier, according to AAA, weighing on consumer sentiment.

Tech stocks offered limited support. Nvidia gained 1.68% after its board authorized an additional $150 billion in share buybacks, bringing total remaining repurchase authorization to $235 billion. However, losses elsewhere offset the gains: MongoDB plummeted 17.2% after its CEO departed to join Meta Platforms, dragging down database and enterprise software peers including Salesforce, ServiceNow, and Snowflake. Boeing slid nearly 7% following disclosure of a 737 Max software glitch affecting landings.

Investors awaited key economic data due later in the week, including the August personal consumption expenditures price index on Wednesday and the September jobs report on Friday, which would shape expectations for future Federal Reserve decisions.

Topics

Politics Iran and Middle East War Business World

#interest rates #Iran tensions #U.S.-Iran tensions #Nasdaq #Brent crude #Treasury yields #Nvidia buyback #S&P 500 #Dow Jones #Federal Reserve

Entities

Why This Matters

U.S. stock market volatility and rising Treasury yields directly affect borrowing costs for businesses and consumers, while elevated oil prices (Brent briefly above $100/barrel) increase operating expenses for airlines, transportation, and energy-intensive sectors. Fed rate-hike expectations (70% probability at October 28 meeting) influence corporate profit margins and household purchasing power. Strait of Hormuz disruption risks to global energy supply create cascading effects across energy markets and related equities. Investors monitor upcoming inflation data (PCE) and September jobs report to assess momentum of Fed tightening.

Timeline & Sources

Feb 28, 2026

Wire

United States and Israel conduct military operation against Iran; oil prices at approximately $72 per barrel

Sep 16, 2026

Wire

Federal Reserve raises interest rates for first time since 2023, lifting rates to between 3.75% and 4%

Oct 3, 2026

Wire

September jobs report due (Friday of following week)

Oct 28, 2026

Wire

Federal Reserve October 28 meeting (70% probability of additional quarter-point rate hike)

Quick Facts

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