US Stocks Close Lower August 31 as WTI Crude Climbs Above $90 on Iran Strike Resumption, Dow Drops 0.70%

The Quick Take

• The Dow Jones fell 0.70% to 53,186, the S&P 500 lost 0.33% to 7,686, and the Nasdaq edged down 0.12% to 26,371 on August 31
• WTI crude oil climbed above $90 per barrel following U.S. military strikes against Iran, reigniting inflation and rate-hike concerns
• Markets pared some losses in the afternoon session as investors bought dips in large-cap growth names including Tesla
• The session capped a month of rising geopolitical risk premiums as the US-Iran conflict resumed after a one-month pause

U.S. equity markets closed August 31 broadly lower as WTI crude oil climbed above $90/barrel following the resumption of U.S. military strikes against Iran — a development that rekindled inflation fears and prompted a repricing of Federal Reserve rate expectations. The Dow Jones Industrial Average fell 0.70% to 53,186, the S&P 500 lost 0.33% to 7,686, and the Nasdaq Composite edged down 0.12% to 26,371. The Nasdaq's relative outperformance reflected afternoon buying in large-cap growth names — particularly Tesla, which surged ahead of its September 3 Cybercab event — partially offsetting the broader energy-driven selloff in consumer and industrial stocks.

The day's trading pattern illustrated the current bifurcation in equity markets: technology and AI-adjacent names continue to attract buying interest on any weakness, while energy-intensive sectors and consumer-facing companies face pressure from the oil price spike. Airlines, logistics companies, and consumer discretionary names led the declines as investors modelled elevated fuel and input costs for Q3-Q4 2026. The bond market also moved against equities, with the 10-year Treasury yield rising as oil-driven inflation expectations repriced Fed rate hike probability upward. The equity risk premium compressed as a result, providing a fundamental valuation headwind beyond the sentiment impact of the oil shock.

August 31 closed one of the more volatile months of 2026 for U.S. markets, as the Iran conflict escalation cycle introduced a geopolitical risk premium that had been largely absent from equity pricing since mid-year. The key data points that September will test: August CPI (scheduled for release in mid-September) will reveal whether oil-driven inflation is entering core metrics; the FOMC September meeting will provide the Fed's updated assessment of the inflation outlook; and Q3 2026 corporate earnings season (beginning in mid-October) will show whether companies are successfully passing through energy cost increases or absorbing margin compression.

Synthesized from 4 sources.