U.S. stocks opened lower,unable to follow through the previous day's modest gains, as weaker-than-expected ADP jobs report set a gloomy tone. More economic signals will come later in the Institute for Supply Management's non-manufacturing survey. Investors will also pay attention to two Fed officials speaking later on Wednesday. The Dow Jones Industrial Average began the session down 11 points, or 0.1%, at 15,416.60. The S&P 500 opened 3.4 points, or 0.2%, lower at 1,750.10. The Nasdaq Composite opened down 9.4 points, or 0.2%, at 4,021.14. Yet another day of despondency.