U.S. equities were mixed at midday, with the Dow Jones Industrial Average and S&P 500 slightly higher and the Nasdaq marginally lower.

Shares of UnitedHealth Group ( UNH -14.89%) are falling on Thursday. The company's stock has plummeted 15% as of 11:33 a.m.

On a conference call to discuss the results, Walmart (WMT) Chief Executive Doug McMillon described the company's immediate challenge as navigating the impact of tariffs. He said cost pressures from ...