Major U.S. stock indices opened lower on Monday, with technology stocks leading the decline. The Dow Jones Industrial Average fell 0.15%, the S&P 500 dropped 0.38%, and the Nasdaq Composite decreased by 0.76%. This dip follows a week of gains, with the S&P 500 still showing a year-to-date increase of over 17% as the year nears its close. Treasury yields also fell in bond market activity.