The Dow and the S&P 500 ended little changed on Wednesday and the Nasdaq dipped after a report on the vast services sector showed only slight improvement in the U.S. economy.

* Investors opted to book profits from some of the technology bellwethers, including Apple Inc , whose recent advance propelled the Nasdaq to a fresh 16-month closing high on Tuesday.

* The Institute for Supply Management (ISM) index showed the service sector grew at marginal pace in December, while the ADP Employment Services report indicated 84,000 job losses in the private sector, compared with a forecast for a drop of 73,000. For details, see [ID:nN06314739] * Based on the latest available data, the Dow Jones industrial average <.DJI> rose 1.66 points, or 0.02 percent, to end unofficially at 10,573.68. The Standard & Poor's 500 Index

<.SPX> edged up just 0.62 of a point, or 0.05 percent, to

finish unofficially at 1,137.14.

But the Nasdaq Composite Index <.IXIC> shed 7.62 points, or 0.33 percent, to close unofficially at 2,301.09.

(Reporting by Ellis Mnyandu; Editing by Jan Paschal)