U.S. equity futures are trading lower after bouncing around between gains and losses.
The major futures indexes are indicating a decline of 1.6 percent.
This follows a more than 1,300 point, or 6.3 percent, decline Wednesday in the Dow Jones Industrial Average, which has now lost nearly all of its gains since President Trump's inauguration. The Dow closed at 19,898.92.
The New York Stock Exchange said Wednesday it will temporarily close its iconic trading floor in lower Manhattan and move to all-electronic trading beginning Monday as a precautionary step amid the coronavirus outbreak.
Signs that the outbreak's impact will be far reaching and prolonged have undermined efforts to staunch the bloodletting on the markets.
Even prices for investments seen as very safe, like longer-term U.S. Treasurys, have been slumping as investors rush to raise cash.
The price of oil fell 24 percent on Wednesday, dropping below $21 per barrel for the first time since 2002. By early Thursday, they had recovered some losses, with U.S. crude up 12.3 percent, or $2.51, at $22.88 per barrel in electronic trading on the New York Mercantile Exchange.
Brent crude, the international standard, was up $1.60 at $26.32 per barrel.
Shares in Asia followed the latest selloff on Wall Street.
Japan's Nikkei gave up 1 percent, Hong Kong's Hang Seng slipped 2.6 percent and China's Shanghai Composite shed 0.9 percent.
Markets have been incredibly volatile for weeks with the rising likelihood that the outbreak will cause a recession.
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The Dow, now at its lowest level since 2016, had surged more than 5 percent on Tuesday after Trump promised massive aid to the economy.
The S&P 500, which dictates how 401(k) accounts perform much more than the Dow, is down nearly 30 percent from its record set last month, though it's still above its level on Election Day 2016.
The S&P 500's slide was so sharp that trading was halted for 15 minutes Wednesday. The losses deepened after trading resumed. The S&P 500 recouped some losses to close 5.2 percent lower, at 2,398.10.
The Nasdaq composite index shed 4.7 percent to 6,989.84.
On Wednesday, President Donald Trump signed an aid package, approved earlier Wednesday by the Senate, to guarantee sick leave to workers who fall ill. Trump's authority under the 70-year-old Defense Production Act gives the government more power to steer production by private companies and try to overcome shortages in masks, ventilators and other supplies.
The European Central Bank, meanwhile, promised 750 billion euros ($817 billion) in asset purchases to support markets.
In European markets, London's FTSE slipped 0.6 percent, Germany's DAX fell 0.7 percent and France's CAC gained 0.3 percent.
The Associated Press contributed to this article.