NEW YORK, Sept. 5 -- U.S. stocks ended narrowly mixed on Wednesday as investors kept cautious before a crucial meeting of the European Central Bank.

When the market closed, the Dow Jones Industrial Average added 11.54 points, or 0.09 percent, to 13,047.48. The Standard & Poor's 500-stock Index slipped 1.50 points, or 0.11 percent, to 1,403.44. The Nasdaq Composite Index fell 5.79 points, or 0.19 percent, to 3, 069.27.

Among 10 big-cap S&P sectors, materials gained, while industrial and utilities lagged.

Major indexes seesawed throughout the session without any significant economic data to direct trading. Investors' focus were still on Europe as the ECB President Mario Draghi is expected to reveal more details about the new round of bond purchasing program after a policy meeting Thursday. The move was aimed at lowering borrowing costs in the debt-ridden members like Spain and Italy.

However, some investors doubt the ECB can announce anything concrete before the German constitutional court rules on the region's bailout funds on Sept. 12.

Also weighing on the market were shares of FedEx, which declined after the package-delivery company slashed its fiscal first-quarter forecast, citing the weak global economy. Some investors believed the downward revision of FedEx's outlook was a bad sign for stocks, as FedEx was generally regarded as a bellwether for the broader economy.

Beyond the ECB meeting, investors are also looking to U.S. non- farm payroll data on Friday. Many investors believed a weaker-than- expected number could add to the chance for the U.S. Federal Reserve to announce further stimulus later this month.