Futures on major U.S. indices point to a lower opening on Wednesday as investors awaited data on the U.S. private sector jobs market from payroll processing firm ADP.

Futures on the S&P 500 are down 0.23 percent, futures on the Dow Jones Industrial Average are down 0.18 percent and Nasdaq100 futures are down 0.19 percent.

Investors will assess the ADP report, which is a measure of the monthly change of nonfarm private employment, for indications of the government's more comprehensive monthly jobs report, which is due on Friday.

The ADP employment report at 8:15 am EDT is expected to show a modest slowdown in job creation, with economists forecasting that the number of private jobs grew by 180,000 in April, after a 209,000 increase in March.

Upbeat U.S. manufacturing data on Tuesday eased worries that the world's biggest economy had lost momentum at the start of the second quarter. The Institute for Supply Management (ISM)'s purchasing managers Index (PMI) improved to 54.8 percent in April from 53.4 percent in March.

The data tops Reuters' expectation for a decline to 53.0 percent and pushed the Dow Jones Industrial Average to close at its highest level in more than four years.

After the surprisingly strong ISM number, the next job data will be more important than usual. If it is strong, it could cement expectations of strong recovery, at least in the United States, Mitsuru Saito, chief economist at Tokai Tokyo Securities, told Reuters.

Meanwhile, factory orders are expected to decline 1.5 percent in March compared to a 1.3 percent gain in February.

On the earnings front, a string of companies, including Mastercard, Comcast Corp, Devon Energy Corp, Visa Inc, Symantec Corp, Whole Foods Market and Time Warner Inc. will report their quarterly earnings.

European markets are currently trading mixed with the FTSE 100 down by 44.50 points, the DAX30 up by 0.97 points and the CAC 40 up by 15.97 points.