US stocks today: S&P 500 and Nasdaq open lower as Iran tensions jolt sentiment, chip stocks slide

US markets opened mixed as escalating US-Iran tensions pushed oil prices higher and weighed on investor sentiment. The S&P 500 and Nasdaq declined, dragged by weakness in chip stocks, while the Dow edged higher amid cautious positioning. Rising geopolitical risk and energy costs are expected to ripple into emerging markets including India, given the country's oil import dependency.