Stocks Tumble as Tech Sector Falls Sharply

Other potential reasons for the market drop: the July trade deficit swelling to $63.6 billion, its highest level in 12 years; Friday's upcoming jobs report (following a slightly better than expected weekly jobless claims report); and the upcoming long Labor Day holiday weekend, prompting profit taking.

In addition, yet another Federal Reserve official expressed the need for additional fiscal relief to sustain the U.S. economy. Chicago Fed President Charles Evans told a virtual meeting of an Indiana Chamber of Commerce branch on Thursday that the absence of additional federal aid or inadequate relief "presents a very significant downside risk to the economy today." 

Fed Governor Lael Brainard expressed similar sentiments earlier this week as well a need for the Fed to provide even more monetary stimulus for the economy and possibly more explicit guidance about its near zero interest rate policy. The Fed recently revamped its policy framework to allow for slightly above-target inflation to support the job market.

Liz Ann Sonders tweeted Thursday that a new survey of managers and executives from the Conference Board "suggests a long, uncertain road ahead," with 35% noting that they don't know when their businesses will reopen and only 14% expecting to return to the workplace by the end of this month.