U.S. stocks closed lower on Monday as escalating U.S.-Iran military tensions and rising Treasury yields weighed on the market. The Dow Jones Industrial Average tumbled 374.09 points, or 0.70%, to close at 53,185.90, while the Nasdaq Composite slipped 0.12% to 26,370.89, and the S&P 500 declined 0.33% to 7,686.14.

In mega-cap tech, losses outpaced gains. Tesla Motors surged more than 5% after the company introduced a stripped-down Model 3 variant in Hong Kong and Macau. Google and Amazon both dropped over 2%, with the U.S. Federal Trade Commission preparing a lawsuit accusing Amazon of deceiving advertising clients. The Philadelphia Semiconductor Index added nearly 0.6%, with Qualcomm jumping 3.83%, Nvidia rising 1.36%, and AMD gaining 1.10%. Memory chipmakers were mixed: SanDisk climbed 5.50%, Micron Technology advanced 2.77%, SK Hynix rose 2.20%, while Seagate Technology slipped 0.17%. Optical communications stocks diverged, with Lumentum up 2.21%, Corning flat at +0.02%, and Coherent down 0.49%.

Utilities badly underperformed the broader market, with PG&E and Edison International both plunging over 20% after California amended its laws to guarantee that survivors of wildfires retain the right to sue utility companies over fire damage caused by electrical equipment. The Nasdaq Golden Dragon China Index dropped 2.19%, with Alibaba falling 4.10%, while Baidu, JD.com, and PDD Holdings each declined more than 1%.

Geopolitical risks in the Middle East have reignited. According to CCTV News reports, on August 30, 2026, U.S. forces bombed two military facilities belonging to Iran's Islamic Revolutionary Guard Corps on Larak Island—the first U.S. military action against Iran in a month. Iran immediately launched retaliatory strikes against several U.S. military targets. On August 31, the General Staff of the Iranian Armed Forces issued a statement declaring that, while respecting the sovereignty of neighboring states, Iran will not tolerate any act of aggression and will respond with even greater force. The statement noted that despite some regional countries officially announcing they would not permit aggressive U.S. forces to use their territory to attack Iran—and despite prior warnings from Tehran—U.S. forces have still used those territories to strike certain Iranian military installations.

Long-dated Treasury yields rose, with the benchmark 10-year note up 3.6 basis points to 4.757% and the 30-year bond adding 4.1 basis points to 5.248%. As the conflict remains deadlocked and shipping through the Strait of Hormuz is disrupted, markets worry that upward pressure on energy prices could spill over into broad systemic inflation, potentially forcing the Federal Reserve to begin raising interest rates as soon as next month. The CME FedWatch tool currently shows financial markets pricing in a better-than-65% probability of a 25-basis-point rate hike at the conclusion of the September FOMC meeting.

Paul Nolte, senior wealth advisor and market strategist at Murphy & Sylvest, said: "Investors are re-evaluating Fed Chair Warsh's remarks at Jackson Hole, assessing their implications for interest rates and inflation. If the Fed doesn't hike in September, we'll see a violent market reaction, because markets have fully priced in a rate increase for a long time."

Despite the recent pullback, the AI trade remains a dominant theme. The Dow rose more than 1% in August, marking its fifth consecutive monthly gain and its 15th positive month out of the past 16. The S&P 500 and Nasdaq each posted their first monthly advance since May, climbing 2.6% and 3.9% respectively—both indices hit record highs earlier in August. Tom Hainlin, investment strategist at U.S. Bancorp Asset Management, said current oil prices are "slightly elevated" but this rally is not yet destructive. "Global oil supply can meet demand; the $80–90 range is not high enough to crush the economy. Prices are just running at the top of that band right now, and they don't change our outlook for consumption, corporate activity, AI, manufacturing reshoring, or the electrification of the economy."

This week brings crucial economic data: the August nonfarm payrolls report on Friday morning, along with monthly manufacturing and services PMI readings. Traders are also monitoring the G20 finance ministers' meeting taking place in Asheville, North Carolina.

In commodities, international oil prices surged, with WTI crude for the front month up 2.83% to $85.76 per barrel, while Brent crude for the front month gained 2.71% to $90.49 per barrel. Precious metals fell, with COMEX gold for September delivery down 1.05% to $4,431.10 per ounce and COMEX silver dropping 1.16% to $66.221 per ounce.