* Netflix tumbles in premarket after quarterly results
* Goldman Sachs falls after earnings
* Initial jobless claims data on tap
* Futures off: Dow 114 pts, S&P 15.5 pts, Nasdaq 33 pts (Updates prices, adds premarket movers)
By Chuck Mikolajczak
NEW YORK, Oct 16 (Reuters) - U.S. stock index futures tumbled on Thursday, after the S&P 500 closed at its lowest in six months, amid concerns about weak global demand and its potential impact on the U.S. economy and businesses.
The S&P 500 and Nasdaq briefly fell into negative territory for the year on Wednesday as the S&P tumbled more than 3 percent to a session low, before rallying late in the session. The decline was also spurred by worries over the spread of the deadly Ebola virus and its possible impact on the travel industry.
The benchmark S&P index has dropped in six of the past eight sessions and is down 7.4 percent from a record closing high Sept. 18. The CBOE Volatility index is up 118 percent since the S&P record, and closed Wednesday at its highest since June 2012. The VelocityShares Daily 2x VIX Short Term exchange-traded note jumped 23.8 percent to $6.04 in premarket.
Earnings reports did little to stem the equity rout. Netflix shares shares plunged 25.9 percent to $332.40 in premarket after it reported quarterly results and said it signed up fewer video-streaming subscribers than forecast for the quarter.
Goldman Sachs shares were off 2.3 percent to $173.25 in premarket trading after posting quarterly results.
Google is expected to report earnings after the closing bell on Thursday.
The earnings of S&P 500 companies are expected to grow 6.7 percent in the third quarter, according to Thomson Reuters data through Wednesday, on revenue growth of 4 percent.
At 8:30 a.m. (1230 GMT), investors will eye weekly initial jobless claims data for insight into the health of the labor market. Expectations call for claims to rise slightly to 290,000 from the 287,000 in the prior week.
At 9:15 a.m. (1315 GMT) industrial production data for September is due, while the NAHB/Wells Fargo Housing Market index and Philadelphia Fed’s manufacturing business outlook for October are due at 10:00 a.m. (1400 GMT).
Baker Hughes were among the most active on the New York Stock exchange, as shares tumbled 11.4 percent to $47.50 after the world’s No.3 oilfield services provider reported a lower-than-expected profit for the first time in five quarters.
Chesapeake Energy was a bright spot before the opening bell, up 6.1 percent to $18.85 after the company sold certain oil and gas assets to Southwestern Energy for about $5.37 billion. Volume of over 325,000 shares placed it near the top of the most active stocks in premarket on the New York Stock Exchange.
* S&P 500 e-minis were down 15.5 points, or 0.84 percent, with 527,633 contracts changing hands.
* Nasdaq 100 e-minis were down 33 points, or 0.88 percent, in volume of 70,370 contracts.
* Dow e-minis were down 114 points, or 0.71 percent, with 85,320 contracts changing hands. (Editing by Bernadette Baum)