Wall Street lower on bank earnings; Wal-Mart hammered

Weak economic data from the United States and China added to worries about the health of the global economy even as investors' focus shifted to company results. "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 8.6 percent to $60.99, on track for its worst one-day performance in more than 17 years, af