U.S. stocks closed lower for a third straight session on August 18, with the Nasdaq Composite dropping 1.33% and underperforming the Dow Jones Industrial Average as higher interest rates and renewed Middle East tensions weighed on risk appetite. The Dow fell 116.38 points, or 0.21%, to 53,343.40, while the Nasdaq lost 355.200 points to 26,289.711. Investor concerns were reinforced by comments from President Donald Trump and Iranian Parliament Speaker Mohammad Bagher Ghalibaf, which kept uncertainty around the Strait of Hormuz in focus and helped lift WTI crude futures 0.5% to $84.94 per barrel. At the same time, heavier corporate bond issuance tied to AI infrastructure spending was seen pushing government bond yields higher, pressuring richly valued technology and semiconductor shares. The benchmark U.S. long-term yield briefly touched 4.74%, its highest since late July, and the 30-year Treasury yield reached 5.338%, the highest since June 2007, before easing from intraday peaks. Semiconductor stocks led the decline, with Nvidia down 2.3%, while Micron Technology, Marvell Technology and Intel were also sold off. Caterpillar fell 4.6%, Boeing dropped 1.3%, and Goldman Sachs and Cisco Systems also traded lower. In contrast, investors rotated into defensive shares, with Johnson & Johnson gaining 3.3% and Salesforce, Nike and Coca-Cola each rising more than 2%, while IBM and Apple also advanced.