* Futures down: Dow 379 pts, S&P 45.25 pts, Nasdaq 133.75 pts
By Tanya Agrawal
Jan 7 (Reuters) - U.S. stock index futures fell sharply on Thursday after China allowed the yuan to fall further and oil prices slid to near 12-year lows, raising concerns over the state of the global economy.
* China allowed the biggest fall in the yuan in five months, and Shanghai stocks slid 7.3 percent to trigger the second trading halt this week.
* With Beijing accelerating the yuan's depreciation to make its exports more competitive, investors fear China's economy is even weaker than had been imagined.
* Oil slid below $33 a barrel to near 12-year lows, as a tumble in Chinese equities rattled investors already concerned by near-record production and massive stockpiles of unwanted crude and refined products.
* European stocks were also at their lowest levels since late August, when concerns over China's economy roiled global stock markets.
* U.S. stocks closed at their lowest level since early October on Wednesday.
* Shares of Apple were down 2.9 percent to $97.80, following reports of slowing shipments of the iPhone 6S and 6S Plus.
* Oil majors Exxon and Chevron were down more than 2 percent, while miner Freeport-McMoRan saw its shares fall 5.2 percent to $5.85.
* Tech majors Facebook, Amazon and Yahoo were all down more than 2.5 percent.
Futures snapshot at 6:35 a.m. ET (1135 GMT):
* Dow e-minis were down 379 points, or 2.25 percent, with 90,751 contracts changing hands.
* S&P 500 e-minis were down 45.25 points, or 2.28 percent, with 507,660 contracts traded.
* Nasdaq 100 e-minis were down 133.75 points, or 3.01 percent, on volume of 96,150 contracts. (Reporting by Tanya Agrawal; Editing by Saumyadeb Chakrabarty)