U.S. stock index futures were higher on Wednesday, set to rebound from a sharp fall on Tuesday and ahead of private employment data for April.

Private payrolls processor ADP is expected to report that private firms added more jobs in April than in March and the numbers will serve as an early snapshot into the larger U.S. employment situation ahead of more comprehensive data on Friday.

The data is expected at 8:15 a.m. ET.

Federal Reserve Chair Janet Yellen will speak at a conference later in the day and markets will be sensitive to any cues on the timing of a rate hike.

European equity indexes rebounded in choppy trade on Wednesday as strong euro zone services data and corporate results offset a sell-off in the region's government bonds and a rise in the euro.

U.S. stocks finished sharply lower on Tuesday after a surprisingly wide March U.S. trade deficit raised concerns that the economy shrank in the first quarter.

MoneyGram (MGI.O) soared 23.3 percent to $9.62 in premarket trading after Bloomberg reported that Western Union (WU.N) was considering buying its smaller rival.

Herbalife (HLF.N) jumped 14.3 percent to $45.81 after the weight-loss and nutritional products maker raised its full-year profit forecast.

Synageva BioPharma (GEVA.O) soared 41 percent to $134.98 after Alexion (ALXN.O) offered to buy the company at a 135.7 percent premium to Tuesday's close. Alexion was down 1.98 percent at $165.21.

MetLife (MET.N), Prudential (PRU.N) and TripAdvisor (TRIP.O) are scheduled to report results after the bell.

Data expected on Wednesday also includes the U.S. non-farm businesses productivity numbers for the first quarter at 8:30 a.m. EDT.

Futures snapshot at 7:16 a.m. EDT:

S&P 500 e-minis ESc1 were up 4.5 points, or 0.22 percent, with 143,226 contracts traded.

Nasdaq 100 e-minis NQc1 were up 1.5 points, or 0.03 percent, on volume of 28,830 contracts.

Dow e-minis 1YMc1 were up 46 points, or 0.26 percent, with 25,694 contracts changing hands.