U.S. stock index futures tumbled on Wednesday, pointing to another volatile session for Wall Street on fears that even dramatic stimulus measures would not be able to avert a deep coronavirus-driven recession.

S&P 500 Futures were down 92 points, or 3.69 percent, at their daily down trading limit, while the SPDR S&P 500 ETFs tumbled 5.6 percent.

Wall Street's main indexes had bounced on Tuesday from a massive selloff a day earlier, as the Trump administration pressed for a 1 trillion U.S. dollar stimulus package and the U.S. Federal Reserve relaunched a plan to purchase short-term corporate debt.

However, with the COVID-19 disease still spreading rapidly across the globe, investors are alarmed about the extent of the blow to consumer spending, businesses and supply chains, sending financial markets into a tailspin.

The rout has also pressured perceived safe havens, such as gold, as traders offloaded their damaged positions, particularly from the aerospace sector.

At 9:54 a.m. GMT, Dow e-minis were down 821 points, or 3.92 percent, and Nasdaq 100 e-minis were down 328 points, or 4.43 percent.