SLIP SLIDIN': U.S. stocks continued a two-day slide Thursday on weak economic data and concern about the Federal Reserve's resolve to keep up its economic stimulus program.

YEAR'S WORST: The Standard & Poor's 500 index was on track for its first weekly decline since December.

WAL-MART WARNS: Wal-Mart Stores rose after beating analysts' profit forecasts in the fourth quarter. However, the biggest retailer warned of a slow start to the year. Wal-Mart said the first three weeks of December were weak, and business has been volatile since then, in part because of delayed tax refund checks and the expiration of a temporary reduction in the payroll taxes.