US stocks open mixed after Thursday's fall

Wall Street's main indexes opened mixed on Friday, a day after Walmart's dour forecast hit sentiment, while UnitedHealth slid after a report that the U.S. Justice Department is investigating the healthcare conglomerate.

The Dow Jones Industrial Average fell 356.5 points, or 0.81%, at the open to 43820.13. The S&P 500 fell 3.4 points, or 0.06%, at the open to 6114.1, while the Nasdaq Composite rose 44.3 points, or 0.22%, to 20006.693 at the opening bell.