The UnitedHealth slide weighed heavily on the Dow, which fell 520 points, or 1.3%, by 9:40 a.m. EDT Thursday.

Two little-known Wall Street companies experienced an “unusual” stock price surge before an announcement naming Donald ...

U.S. stocks were mixed at the open on Thursday as the S&P 500 and Nasdaq Composite rebounded from a Wednesday afternoon selloff, while a sharp drop in the shares of UnitedHealth Group weighed on the ...