US Markets Rise on AI Rally, Falling Oil, and Easing Yields

U.S. stock markets rose on Monday, September 21, 2026, with major indexes posting solid gains as investors reacted to a rally in artificial intelligence and semiconductor stocks, a sharp decline in oil prices, and easing Treasury yields. The positive momentum reflected a confluence of factors, including cautious optimism ahead of a high-stakes summit between U.S. President Donald Trump and Chinese President Xi Jinping scheduled for later this week. The Dow Jones Industrial Average gained 0.47% to 51,923.89 in morning trading, according to Reuters. The S&P 500 advanced 0.92%, while the Nasdaq Composite climbed 1.48%, led by strong performance in technology shares. The rally was broad-based, with AI-related companies at the forefront. Intel rose approximately 9%, AMD gained 8.5%, and Micron advanced 3%. AMD's surge pushed its market valuation above the $1 trillion mark. Meta Platforms also moved higher after receiving a price target increase from Wells Fargo. A significant driver of the market's advance was a steep drop in crude oil prices, which eased concerns about energy-driven inflation. Brent crude fell between 2.6% and 3.2% to a range of $100.50 to $101.20 per barrel.