U.S. stock index futures edged higher on Tuesday following the largest losses on Wall Street since early October and ahead of a large data batch that will show the momentum of the U.S. economy at the end of last year.

* Two separate readings on the U.S. services sector growth in December are due shortly after the opening bell. A gauge of durable goods and factory orders for November is due at 10 a.m. EST as well as an index of economic optimism for January.

* The S&P 500 fell 1.8 percent to post its worst day in almost three months on Monday, with energy shares leading the decline as global economic concerns were compounded by swooning oil prices. The energy sector of the S&P 500 fell 4 percent.

* Crude oil prices continued to fall on Tuesday, with Brent LCOc1 down as much as 3.5 percent and U.S. crude CLc1 down as much as 3.1 percent.

* AOL Inc (AOL.N) shares rose 6.8 percent in premarket trading the day after a report that Verizon Communications (VZ.N) approached AOL about a potential acquisition or joint venture. The Bloomberg story cited people with knowledge of the matter.

* Shares of Minerva Neurosciences (NERV.O) rose 62 percent premarket the day after data showed an analog of the company's experimental compound showed improvements in treating symptoms of Parkinson's disease in primates.

Futures snapshot at 7:21 a.m.:

* S&P 500 e-minis ESc1 were up 2.75 points, or 0.14 percent, with 167,374 contracts changing hands.

* Nasdaq 100 e-minis NQc1 were up 3.5 points, or 0.08 percent, in volume of 26,679 contracts.

* Dow e-minis 1YMc1 were up 24 points, or 0.14 percent, with 28,787 contracts changing hands.