Stocks lost momentum after Monday’s sharp technology-fueled rally as concerns over AI disruption and geopolitical tensions came to the forefront. The S&P 500 was little changed, while the Nasdaq Composite rose 0.5% and the Dow Jones Industrial Average declined 185 points, or 0.4%. The update appeared in the Markets P.M. newsletter, a recap of the day’s key market moves delivered after the closing bell.