U.S. stocks fell for a third consecutive session on August 18 as a semiconductor and technology selloff pressured the Nasdaq, despite the S&P 500 remaining near record highs. The Dow Jones Industrial Average declined 0.22%, the S&P 500 lost 0.69% and the Nasdaq dropped 1.33%, while the VIX volatility index rose 4.28%. AI-linked shares including Baidu, CoreWeave, Teradyne, Marvell and Micron tumbled, and rising Treasury yields, Middle East tensions and valuation concerns around the AI trade added to the cautious backdrop.