Dow Industrial Average Futures were down by about 300 points, or 1.2 percent, in pre-market trading, implying a sharply lower opening on Thursday after falling more than 3 percent on Wednesday.
This would mark the sixth straight day of losses for the market, which has been rattled by rising interest rates, signs of a slowdown in the global economy and the US-China trade dispute.
Oil prices fell more than 2 percent as U.S. stocks plunged, even though energy traders anxious about shrinking supply from Iran due to U.S. sanctions and kept an eye on Hurricane Michael, which closed almost 40 percent of U.S. Gulf of Mexico output.
The Dow Jones Industrial Average gave up 831.83 points, or 3.1 percent, to 25,598.74. In 1987, stocks dropped more than 20 percent on a single day-Black Monday, Oct. 19-after a strong rally crashed into the Persian Gulf turmoil and trade deficits.
Tech stocks and companies that sell non-essentials to consumers have been some of the top performers over the previous year, gaining almost twice as much ground as the S&P 500. The Nasdaq dropped more than 4% in the worst percentage decline since June 2016.
At its worst, the Dow Jones index dropped by as much as 699 points, before closing 546 points (2.1 per cent) lower at 25,053. It was at just 3.05% early last week and 2.82% in late August. Amazon skidded 4.8 per cent to $1,781.21 (U.S.).
Asian markets tumbled on Thursday, after Wall Street slumped on a heavy selling of technology and internet stocks.
Interested in Stock Market?Stocks had come close to big drops in the last few days, but each time they recovered some of their losses.
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On Tuesday, footage and identities of the "assassination" squad were made public. "It's a very serious situation for us". Riyadh insisted the Khashoggi left the building and called the murder claims "baseless".
The recent turbulence in financial markets is a contrast to what investors have grown accustomed to in a bull market that has lasted more than 10 years, the longest in history. Amazon, Apple, Alphabet and Facebook all fell by between 2.3pc and 3.9pc.
Bond prices rose. The yield on the 10-year Treasury fell to 3.17 percent.
Earlier on Wednesday, Sears Holdings plunged on reports that the struggling retailer is preparing to file for bankruptcy. Sears has closed hundreds of stores and sold several famous brands or put them on the block as it sees more customers abandon its stores.
Oil futures fell. USA crude gave up $1.27 to $71.90 a barrel.
Gold rose 0.2 per cent to $1,193.40 an ounce.
The dollar fell to 111.94 yen from 112.59 yen, and the euro rose to $1.1594 from $1.1525.
Japan's Nikkei 225 added 0.2 percent, South Korea's Kospi dropped 1.1 percent and the Hang Seng in Hong Kong gained 0.1 percent. The British pound rose to $1.3197 from $1.3146.