U.S. stocks were poised to open little changed on Wednesday as investors weighed a fresh round of proposed acquisitions against a weaker-than-expected employment report.

U.S. private employers added 179,000 jobs in April, short of economists' expectations of 198,000, a report by the payrolls processor showed.

It wasn't a huge miss and ADP isn't necessarily always accurate in predicting the U.S. government employment numbers. But it's a miss nonetheless and shows the economy continue to improve but at a very slow, modest rate, said Tim Ghriskey, chief investment officer of Solaris Asset Management in Bedford Hills, New York.

S&P 500 futures added 1.6 points and were slightly above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures added 2 points, and Nasdaq 100 futures rose 1.75 points.

Chip equipment maker Applied Materials Inc is snapping up rival Varian Semiconductor Equipment Associates Inc for $63 per share in cash to acquire new technology to meet increased demand for smartphones and solar equipment.

Varian shares surged 51.6 percent to $61.48 in premarket trade.

We still have some earnings going on and we are getting more and more M&A deals and that is certainly a positive for the market on multiple fronts, said Ghriskey.

The ISM non-manufacturing index for April is due at 10 a.m. EST [1400 GMT], with economists forecasting a tick up to 57.4 from 57.3 in the previous month on growth in its business activity index.

ConAgra Foods Inc raised its offer for Ralcorp Holdings Inc to $86 a share in cash from $82 in cash and stock as it seeks to grow its private-label food business.

Ralcorp jumped 6.7 percent to $88.90 premarket, and ConAgra added 1 percent to $25.

Corporate profit reports were continuing to filter in as earnings season begins to wind down. Through Tuesday, with 360 of the S&P 500 companies reporting, 71 percent had earnings that topped estimates, according to Thomson Reuters data.

Kellogg Co lost 2.1 percent to $56.26 after the cereal and snack maker posted lower-than-expected quarterly profit on higher costs for ingredients and brand investments.

Las Vegas Sands Corp dropped 6 percent to $43.10 premarket after its Singapore casino-resort posted lower-than-expected profit.

Whole Foods Market Inc and News Corp are due to report later in the day.

(Reporting by Chuck Mikolajczak; editing by Jeffrey Benkoe)