U.S. authorities on Tuesday accelerated testing to gauge the spread of the coronavirus as stumped investors struggle to diagnose the deadly virus's economic fallout. Markets sloshed in big, nail-biting swings that have become commonplace in recent days.

Stocks surged on Friday to end a tumultuous week marked by some of the biggest extremes in trading history. Heading into the weekend, most investors are stranded deeply in the red for 2020 and trying to sort through the economic unknowns of the coronavirus.