Stock index futures suggested a higher open on Wednesday after better-than-expected data out of China and Germany and as Greece inched closer to a debt deal, though recent market action suggested gains could be ephemeral.

Volatility was expected to persist, with low trading volume and uneven corporate earnings and weaker employment data adding to the mix.

Amazon could pressure the Nasdaq after a disappointing earnings report late Tuesday.

Gains in index futures eased after the ADP National Employment Report showed the pace of private sector job creation slowed more than expected in January after a sharp gain the month before.

China's factory sector expanded slightly in January, confounding expectations for a contraction and supporting hopes the world's second biggest economy will avoid a hard landing. Separately, Germany recorded its first rise in manufacturing output in seven months.

The market is bullishly higher, given the strong data from China and Europe, ADP may have tempered some enthusiasm and set up some trepidation for what Friday's payroll report might hold, said Mark Luschini, chief investment strategist at Janney Montgomery Scott in Philadelphia. There is brinksmanship between the optimism and a reserved posture for the labor market.

S&P 500 futures rose 8.5 points and were 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 89 points, and Nasdaq 100 futures rose 10.75 points.

Greek Finance Minister Evangelos Venizelos said talks between Greece and its private creditors were one formal step away from a deal needed to avoid a messy default.

Banks continued a trend of rallying on signs of euro zone progress. U.S.-traded shares Deutsche Bank climbed 3 percent to $43.95 while Citigroup Inc rose 1.2 percent to $31.10 before the bell.

The FTSEurofirst 300 <.FTEU3> index of top European shares rose 1.3 percent while an index of European banks <.SX7P> advanced 2.8 percent. <.EU> Inc slumped 9.4 percent to $176.25 in premarket trading a day after warning of a possible first-quarter loss and posting a steep drop in fourth-quarter profit.

Earnings continue to be a mixed bag. According to Thomson Reuters data, of the 204 companies in the S&P 500 that have reported results so far, 59.8 percent topped estimates, tracking below the beat rate at this stage of the earnings season in recent quarters.

Aetna Inc posted sharply higher quarterly profit in line with Wall Street's target early Wednesday.

Whirlpool Corp reported a drop in sales on weak global demand but gave an optimistic full-year outlook, sending shares up 7.5 percent to $58.40 before the bell. Also, Marathon Oil Corp swung to a fourth-quarter loss.

Facebook is expected to submit paperwork to regulators Wednesday morning for a $5 billion initial public offering and selected Morgan Stanley and four other bookrunners to handle the mega-IPO, sources said told Reuters unit IFR.

The January ISM manufacturing report will be released at 10 a.m. EST, and is seen rising at 54.5 from 53.1 in December.

Wall Street closed its best month since October on a flat note on Tuesday, pressured by weaker-than-expected economic reports, including on consumer confidence and home prices, pressured sentiment.

(Reporting by Ryan Vlastelica; editing by Jeffrey Benkoe)