The US stock market plunged as much as 7% immediately after regular trading began on Monday, prompting the first halt since the depths of the financial crisis in December 2008.
The losses came amid a raging global oil-price war and continued fallout from the coronavirus.
All three major US indices tanked as investors mulled the oil markets chaos between Saudi Arabia and Russia.
The virus's rising US death toll prompted new fears of an economic slowdown. Coronavirus is so far responsible for 21 deaths and 554 infections throughout the US.
Stocks plummeted 7% at Monday's market open, prompting the first market-wide trading halt since the depths of the financial crisis in December 2008. The losses came as an oil price war and the escalating coronavirus hammered risk assets from all sides.
The three major US indices declined as equities investors digested the weekend's oil market news for the first time. The commodity tanked the most since 1991 on Monday morning after Saudi Arabia's surprise price cuts kicked off a production war with Russia. The move follows Russia's refusal to curb oil production on Friday to prop up the coronavirus-rattled market.
Coronavirus concerns continued to weigh on investors as outbreaks grew in New York, California, and Florida, among other states. The US death toll now stands at 21 people, and the recent surge in confirmed cases could stifle economic activity by weakening consumer spending behavior.
The coronavirus has so far killed more than 3,800 people and infected more than 110,000.
Here's where major US indexes stood as 9:50 a.m. ET:
S&P 500: 2,755.16, down 7.3%
Dow Jones Industrial Average: 23,836.69, down 7.8% (2,028.09 points)
Nasdaq 100: 7,969.13, down 7.1%
The negative open extends the stock market sell-off into its third week. Equities tanked for seven days in a row to close out February as fears of coronavirus' economic toll caught up with stocks' lofty valuations. Risk assets recovered in March's first trading session before intense price swings saw the market close Friday having erased nearly all month-to-date gains.
Central banks around the world issued emergency stimulus to counteract any economic hit caused by the outbreak.