Wall Street is retreating from its record as a slide for Walmart weighs on U.S. stock indexes Thursday. The S&P 500 was down 0.6% in morning trading after setting all-time highs in each of the last two days.

U.S. stocks crept to a record as the S&P 500 nudged higher after a quiet Tuesday of trading. The main measure of Wall Street's health rose 0.2% to finish just above its all-time closing high set last month.

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