Dow slumps as Wal-Mart hammered after weak forecast

The S&P 500 fluctuated following mixed bank results and disappointing economic data from the United States and China. "The major theme, not only today but through the balance of the earnings season, is going to be the revisions to fourth quarter and 2016 earnings," said Bill Northey, chief investment officer of the private client group at U.S. Bank. Wal-Mart sank almost 10 percent to $60.18, poised for its worst one-day performance in more than 17 years, after it forecast a drop of up to 12