* ADP private payrolls data due
* U.S. services sector readings expected after the open bell
* Major index futures up less than 0.1 percent each
By Rodrigo Campos
NEW YORK, Dec 3 (Reuters) - U.S. stock index futures were flat in low volume on Wednesday ahead of data on the services sector and as markets focus on readings on the U.S. economy and the upcoming meeting at the European Central Bank.
* Separate readings on the health of the U.S. services sector are due shortly after the market open on Wall Street, while ADP's reading on employment creation in the private sector is due at 8:15 a.m. EST (1315 GMT).
* Data showed the euro zone economy may face another contraction after business activity grew less than expected in November despite heavy discounting, although Asian readings were more upbeat. The euro was trading at its lowest against the U.S. dollar in more than two years.
* Momentum is building for the ECB to launch a program of sovereign-bond buying to boost the bloc's struggling economy with most signs pointing to March for a decision. The ECB meets on Thursday.
* On Tuesday, U.S. stocks rose as energy stocks led the S&P 500 and Dow, while Biogen's rally on news about an experimental treatment for Alzheimer's disease topped gains at the Nasdaq. The Dow closed at a record high.
Futures snapshot at 7:18:
* S&P 500 e-minis were up 0.25 points, or 0.01 percent, with 77,062 contracts changing hands.
* Nasdaq 100 e-minis were up 2 points, or 0.05 percent, in volume of 9,600 contracts.
* Dow e-minis were up 4 points, or 0.02 percent, with 16,058 contracts changing hands.
Reporting by Rodrigo Campos; Editing by Chizu Nomiyama