* Facebook slumps in premarket after earnings
* Initial jobless claims, Chicago PMI data on tap
* Futures: Dow up 5 pts, S&P off 0.5 pt, Nasdaq off 7 pts
By Chuck Mikolajczak
NEW YORK, Jan 31 (Reuters) - U.S. stock index futures were little changed on Thursday ahead of data on the labor market and a slew of corporate earnings reports.
Facebook Inc shares lost 4.6 percent to $29.83 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 6.3 percent to $67.55 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.
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 and is virtually flat for the week, hovering near the 1,500 mark, as investors look for more catalysts to justify further gains.
"We've got a handful of economic data today that might move the needle for the market and we've got plenty to contemplate as we continue to get through a plethora of earnings reports as well, so I'm not surprised to see us sideways," said Art Hogan, managing director of Lazard Capital Markets in New York.
"Whether you look at the fears over sequestration (broad government spending cuts set to take effect March 1) which is next month's business, or you consider the jackrabbit start to the year that is not sustainable, or you start to contemplate the weak patches in the economic data stream that we have seen in pieces - all of that combines for a wall of worry for this market to climb and it's building."
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.
United Parcel Service Inc lost 2.1 percent to $79.49 in premarket trading after the world's largest parcel delivery company reported a net loss in the fourth quarter after a $3 billion one-time charge from pension accounting, and forecast that 2013 earnings would rise 6 percent to 12 percent.
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 0.5 point and were slightly 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 7 points.
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.
WMS Industries Inc surged 56.2 percent to $25.57 in premarket after the company agreed to be acquired by Scientific Games Corp for $26 per share in cash. Scientific Games advanced 1.8 percent to $9.09.