Stock futures slipped as traders watched oil prices, the U.S.-Iran war, and the potential impact of these conflicts on the economy. The S&P 500 and the 30-stock Dow both declined, while the Nasdaq Composite managed a slight gain. Energy, tech and communication services were the only sectors that closed in positive territory. President Donald Trump also announced plans to tap the Strategic Petroleum Reserve to reduce energy costs. This comes after the president predicted that the war will end "very soon", which had previously led to a surge in oil prices.