* Facebook slumps in premarket after earnings
* Initial jobless claims, Chicago PMI data on tap
* Futures: Dow +5 pts, S&P off 1.4 pts, Nasdaq off 9.75 pts
By Chuck Mikolajczak
NEW YORK, Jan 31 U.S. stock index futures edged lower on Thursday ahead of data on the labor market and a slew of corporate earnings reports.
* Facebook Inc shares dropped 6.7 percent to $29.14 in premarket trading. The company doubled its mobile advertising revenue in the fourth quarter but that growth trailed some of Wall Street's most aggressive estimates.
* Qualcomm Inc gained 6 percent to $67.35 in premarket trading after the world's leading supplier of chips for cellphones beat analysts' expectations for quarterly profit and revenue and raised its financial targets for 2013.
* Investors will look to weekly initial jobless claims data at 8:30 a.m. ET (1330 GMT) for clues on the health of the labor market ahead of the payrolls report on Friday. Economists in a Reuters survey forecast a total of 350,000 new filings compared with 330,000 in the prior week.
* Also at 8:30 a.m. (1330 GMT), the Commerce Department will release December personal income and spending data; economists expect a 0.8 percent rise in income and a 0.3 percent increase in spending.
* ConocoPhillips reported a drop in quarterly profit as oil and gas prices weakened and output from the third-largest U.S. oil and gas producer remained steady compared with a year ago, though it anticipated a decline in the first quarter.
* Later in the session at 9:45 a.m. (1445 GMT), the Institute for Supply Management Chicago releases January index of manufacturing activity. Economists in a Reuters survey forecast a reading of 50.5 compared with 50.0 in December.
* S&P 500 futures fell 1.4 points and were below 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 rose 5 points, and Nasdaq 100 futures lost 9.75 points.
* The S&P 500 is up 5.3 percent for the month, as legislators in Washington temporarily sidestepped a "fiscal cliff" of automatic tax increases and spending cuts that could have derailed the economic recovery, and amid improving economic data and better-than-expected corporate earnings.
* But the benchmark index has stalled recently, hovering near the 1,500 mark over the past four sessions as investors look for more catalysts to justify further gains.
* Thomson Reuters data through Wednesday morning shows that of the 192 companies in the S&P 500 that have reported earnings this season, 68.8 percent have exceeded expectations, a higher proportion than over the past four quarters and above the average since 1994.
* Overall, S&P 500 fourth-quarter earnings are forecast to have risen 3.8 percent. That's above the 1.9 percent forecast from the start of the earnings season, but well below a 9.9 percent fourth-quarter earnings growth forecast on Oct. 1, the data showed.
* European shares fell as investors digested mixed earnings reports, with a warning from AstraZeneca knocking its shares while Ericsson surged after fourth-quarter results.
* Asian shares fell slightly after rallying to multi-month highs, and more for some Southeast Asian markets, while the U.S. Federal Reserve's pledge to retain its stimulus policy undermined the dollar.
Our top photos from the last 24 hours.