Tech drags S&P 500, Nasdaq lower as Iran tensions, Nvidia earnings loom

On Monday, the S&P 500 and Nasdaq experienced declines, primarily driven by technology stocks, amid investor concerns over potential fallout from the U.S. pledge of an "economic D-Day" against Iran and upcoming Nvidia earnings. The day marked a cautious beginning to a week that may determine equities' resilience against Middle East tensions and bond market volatility.

U.S. Treasury Secretary Scott Bessent, who warned of an "economic D-Day," was set to hold a press conference later in the day. The U.S. threatened sanctions on Iran’s trade partners, causing chip stocks to tumble, with the Philadelphia SE Semiconductor index down 2.64% to a three-week low. Nvidia, Micron Technology, and Broadcom also saw declines, pressuring the S&P 500 IT index.

Financials, however, saw gains, contributing to a modest rise in the blue-chip Dow. Treasury yields remained above 5%, prompting speculation that Bessent might tap the Treasury’s $1 trillion General Account to support bond buybacks. Nvidia's quarterly results and Federal Reserve Chair Kevin Warsh's Jackson Hole speech were expected to be key market drivers.

Nvidia needed to impress to maintain market stability, while Warsh needed to provide clarity on interest rates. Traders also eyed the upcoming Personal Consumption Expenditures report, which indicated a potential 25-basis-point interest rate hike by year-end. U.S. President Donald Trump announced higher tariffs on Canadian automotive parts, affecting automakers and trucking stocks.

On the NYSE, declining issues outnumbered advancers by a 1.14-to-1 ratio, while the Nasdaq saw 62 new highs and 70 new lows.