* Shares in bluebird bio jump on drug study data
* Wholesale trade data due
* Futures off: Dow 127 pts, S&P 15.5 pts, Nasdaq 33.25 pts (Adds premarket actives data)
By Chuck Mikolajczak
NEW YORK, Dec 9 (Reuters) - U.S. stock index futures declined on Tuesday, putting the S&P 500 on track to extend losses after suffering its biggest drop since Oct. 22 in the prior session on concerns about global growth.
* The benchmark S&P index fell 0.7 percent on Monday, dragged lower on weakness in the energy sector, which fell 3.9 percent to hit its lowest level since June 2013. The S&P 500 has climbed for seven straight weeks, closing on Friday at a new record high for the 49th time this year.
* Brent crude touched a fresh five-year low on Tuesday before rebounding near $67 a barrel on hopes prices may be bottoming. Oil prices have been under pressure as the dollar has strengthened and OPEC decided against an output cut.
* In a relatively light week for economic data, wholesale trade data for October is due at 10 a.m. (1500 GMT). Expectations call for inventories to rise 0.2 percent while sales are expected to rise by 0.1 percent.
* U.S.-listed shares of Seadrill gained 3.1 percent to $11.93 before the opening bell. John Fredriksen, the biggest owner of the offshore driller, purchased another 1.3 million shares in the firm to raise his stake to 119 million shares, or 24.15 percent. The stock was the second most-actively traded issue on the New York Stock Exchange in premarket with volume of over 250,000 shares.
* Shares in bluebird bio surged 52.8 percent to $74.70 in premarket trade after the company said a study for its blood disorder treatment showed patients were essentially cured. Volume of over 300,000 shares represented nearly 70 percent of its 10-day average.
* Conn's Inc tumbled 39.7 percent to $21.16 in premarket after the home appliance retailer posted third-quarter earnings and withdrew its 2015 outlook. In addition, the company said its CFO Brian Taylor had resigned.
Futures snapshot at 8:18 a.m EST (1318 GMT):
* S&P 500 e-minis were down 15.5 points, or 0.75 percent, with 227,100 contracts changing hands.
* Nasdaq 100 e-minis were down 33.25 points, or 0.78 percent, in volume of 41,471 contracts.
* Dow e-minis were down 127 points, or 0.71 percent, with 34,684 contracts changing hands. (Reporting by Chuck Mikolajczak; Editing by Chizu Nomiyama and Nick Zieminski)