* Futures down: Dow 156 pts, S&P 16 pts, Nasdaq 39 pts
By Tanya Agrawal
Dec 11 (Reuters) - U.S. stock index futures were sharply lower on Friday as crude oil prices hit 7-year lows on growing oversupply concerns.
* The sharp drop in oil prices adds to investor uncertainty as the U.S. Federal Reserve prepares to raise interest rates for the first time since June 2006 at its meeting next week.
* Adding to the somber mood, China's yuan fell to its lowest in 4-1/2 years on concerns about the country's slowing economy and expectations of a U.S. rate hike.
* Global shares were lower amid concerns that weakness in the Chinese currency could weigh on the global economy and on companies with strong export ties to China.
* Investors are also awaiting U.S. data, which could cement expectations that the Fed is gearing up to hike rates at its Dec. 15-16 meeting.
* Fed fund futures place an 85 percent chance of a hike. A recent Reuters poll also showed that all but one of 18 brokerages that deal directly with the central bank expect a rate increase.
* U.S. retail sales likely picked up in November, which could ease concerns about tepid consumer spending in the fourth quarter. A Reuters survey of economists shows retail sales likely increased 0.3 percent last month, after inching up 0.1 percent in October. That data is expected at 8:30 a.m. ET (1330 GMT).
* Market analysts expect the University of Michigan's preliminary consumer sentiment index to increase to 92.0 in December from 91.3. The report will be released at 10 a.m. ET.
* DuPont shares were down 4.8 percent at $71.00 in premarket trading after the company agreed to merge with Dow Chemical in a deal valuing the combined entity at $130 billion. Dow was up 1.71 percent at $55.78.
* United Technologies was up 1.42 percent at $95.20 after announcing a $1.5 billion restructuring plan to reduce costs.
* SunEdison was up 6.4 percent at $4.35, a day after the company said it would sell wind assets for $209 million.
Futures snapshot at 6:56 a.m. ET:
* S&P 500 e-minis were down 15.75 points, or 0.77 percent, with 124,099 contracts traded.
* Nasdaq 100 e-minis were down 39.25 points, or 0.85 percent, on volume of 16,016 contracts.
* Dow e-minis were down 156 points, or 0.89 percent, with 14,529 contracts changing hands. (Reporting by Tanya Agrawal, Editing by Anil D'Silva)