U.S. stock markets declined on August 31 as rising crude oil prices intensified inflation concerns and increased expectations for tighter monetary policy. The volatility marked the end of a month in which all three major indexes nevertheless recorded gains.
The Dow Jones Industrial Average dropped 374.09 points, or 0.7%, to 53,185.90. The S&P 500 fell 25.62 points, or 0.33%, to 7,686.14, while the Nasdaq Composite slipped 31.53 points, or 0.12%, to 26,370.89. Despite the pullback, the indexes ended August with positive monthly returns. The Nasdaq posted the largest percentage advance, driven by continued interest in artificial intelligence investments, while the Dow extended its streak to five consecutive monthly advances.
The sell-off was largely attributed to a surge in oil prices amid escalating tensions in the Middle East and concerns about ongoing disruptions to energy supply. The closure of the Strait of Hormuz, a strategic oil shipping route affected by regional hostilities, has added pressure on the global energy market and fueled inflationary fears.
Investors also responded to hawkish comments made by Federal Reserve Chair Kevin Warsh during the Jackson Hole economic symposium on August 28. Warsh’s remarks have reinforced expectations that the Federal Reserve will raise interest rates by 25 basis points at its policy meeting scheduled for September.
Market participants placed a more than 65% likelihood on a rate hike in September, according to the CME’s FedWatch tool. “The odds now favor a rate hike in September,” said Peter Tuz, president of Chase Investment Counsel in Charlottesville, Virginia. “Combine that with ongoing geopolitical tensions and low trading volume ahead of Labor Day, and you get a less favorable environment for stocks.”
Paul Nolte, senior wealth advisor at Murphy & Sylvest in Elmhurst, Illinois, noted that markets have largely priced in the September rate increase, warning that any decision to delay could provoke a strong negative reaction.
Within the S&P 500 sectors, energy shares recorded the highest gains, boosted by rising crude prices. Companies such as Halliburton and Valero Energy each rose about 1.9%. Conversely, utility stocks underperformed, weighed down by recent legislative amendments in California that failed to address wildfire-related liability issues for grid operators. Notably, Pacific Gas & Electric (PG&E) fell 20.1%, marking its largest single-day percentage drop in over six years.
On the New York Stock Exchange, declining stocks outnumbered advancing issues by nearly two to one, with 234 new lows compared to 112 new highs reported for the day.
Internationally, Iranian President Masoud Pezeshkian stated that Tehran continues to pursue a negotiated resolution to the ongoing conflict despite recent escalation in airstrikes and the imposition of new U.S. economic sanctions under the administration of President Donald Trump.
The combination of geopolitical instability and monetary tightening creates a challenging backdrop for investors as they assess risk and position portfolios ahead of the Federal Reserve’s next move.