U.S. stocks opened higher on Monday even as investors digested news on tariffs and trade. The Dow Jones Industrial Average DJIA, -0.36% rose 54 points, 0.2%, to open near 28,105. The S&P 500 SPX, -0.57% was up 2.4 points, 0.1%, to open near 3,143. The Nasdaq COMP, -0.96% was 2 points, less than 0.1%, higher, at the open, and immediately gave up those gains. Shares of McDermott International Inc. MDR, +5.73% soared double digits after the engineering and construction services company said it had reached agreements with some of its creditors.