A sharp slide for Walmart on Thursday helped pull Wall Street off of its record. The S&P 500 slipped 0.4% for its first drop after setting all-time highs in each of the last two days. The Dow Jones Industrial Average lost 450 points,

Microsoft was the strongest force pushing the S&P 500 upward. It rose 1.3% after saying it had developed what it calls the world’s first “quantum processing unit,” which cou