U.S. stocks were mixed on Monday as semiconductor and other AI-linked shares outperformed while geopolitical tension in the Middle East lifted oil and haven assets. By midday in New York on the 18th, the Philadelphia Semiconductor Index, or SOX, had risen 332.10 points, or 2.67%, to 12,749.15 and the Nasdaq Composite added 26.55 points to 26,755.71, while the Dow Jones Industrial Average fell 188.26 points to 53,544.15 and the S&P 500 slipped 12.75 points to 7,773.01; later afternoon quotes showed the Nasdaq near flat at 26,718.2. Reports that Amazon-backed Anthropic told potential investors its second-quarter revenue rose at least 14-fold from a year earlier to more than $11.5 billion supported technology shares. At the same time, President Donald Trump's threat against Oman as the U.S.-Iran peace deadline expired, and a senior Iranian official's statement that Iran had shifted to a "full offensive," kept focus on the Strait of Hormuz, helping lift crude to about $82.7 a barrel and gold to roughly $4,483 an ounce.