U.S. stocks were wavering after a strong rally in the previous session ahead of chip maker Nvidia’s quarterly earnings, which are seen as a potential make-or-break moment for the artificial intelligence trading craze. Dow Jones Industrial Average futures were down 39 points, or 0.1%, after the index set a new record closing high on Monday. S&P 500 futures also falling 0.1%, while contracts tied to the tech-heavy Nasdaq 100 were edging down less than 0.1%.