* Netflix jumps after earnings
* eBay rises after results, Icahn spin-off proposal
* Initial claims, existing home sales data due
* Futures off: Dow 69 pts, S&P 6.75 pts, Nasdaq 4.5 pts
By Chuck Mikolajczak
NEW YORK, Jan 23 (Reuters) - U.S. stock index futures fell on Thursday, ahead of data on the labor and housing markets, along with the latest round of corporate earnings results.
* Investor sentiment was dented by a report on manufacturing in China, as the flash Markit/HSBC Purchasing Managers' Index fell in January from the prior month, suggesting that a mild slowdown at the end of 2013 in the world's second-largest economy had continued into the new year.
* At 8:30 a.m. EST (1330 GMT), investors will eye weekly initial jobless claims data for signs of improvement in the labor market. Expectations call for 326,000 claims, equal to the prior week.
* Existing home sales data for December is expected at 10:00 a.m. (1500 GMT). Sales are expected to climb slightly to 4.94 million against 4.9 million in the prior month.
* Netflix Inc shares surged 16.5 percent to $388.85 before the opening bell. The world's largest video-streaming company's quarterly earnings late Wednesday showed it added more than 2.3 million U.S. customers in the fourth quarter.
* eBay Inc climbed 3.5 percent to $56.30 in premarket trading. The e-commerce giant reported earnings a day earlier and said activist investor Carl Icahn had submitted a proposal to spin off eBay's PayPal business, a plan the company dismissed.
* Earnings are expected from 21 S&P 500 companies on Thursday, including Dow component McDonald's Corp and railroad Union Pacific Corp. Microsoft Corp and Starbucks Corp are expected to report after the close.
* According to Thomson Reuters data through Wednesday morning, earnings for the fourth quarter are expected to grow 7.2 percent over the prior year. Of the 80 companies in the benchmark S&P index that have reported, 61.3 percent have topped analyst expectations, below both the long-term average of 63 percent and the 67 percent average over the past four quarters.
* S&P 500 e-mini futures fell 6.75 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 lost 69 points and Nasdaq 100 futures declined 4.5 points.
* Top U.S. weapons maker Lockheed Martin Corp reported lower-than-expected earnings after charges linked to U.S. defense budget cuts and workforce reductions, but said it expected higher earnings this year.
* European shares were flat as a recovery in economic activity in much of the region offset another mixed batch of corporate earnings news and unexpectedly weak China data. The manufacturing survey in China pulled Asian markets lower.