Wall Street's main indexes tumbled about 2 percent on Friday after a raft of weak manufacturing data from the United States and Europe led to an inverted yield curve, stoking fears of an economic slowdown.
Manufacturers in Europe, Japan and the United States suffered in March as surveys showed trade tensions had impacted factory output, a setback for hopes the global economy might be turning the corner on its slowdown.
This led to the spread between three-month Treasury bills and 10-year note yields inverting for the first time since 2007. An inverted yield curve is widely understood to be a leading indicator of recession.
"Right now there are clearly enough signs to be cautious about a number of factors that can potentially cause an economic recession," said Randy Frederick, vice president of trading and derivatives for Charles Schwab in Austin, Texas.
Financial stocks took the biggest hit, tumbling 2.94 percent, the most among the 11 main S&P sectors. The banking sector plunged 4 percent.
The Federal Reserve earlier this week abandoned projections for any interest rate hikes this year, as policymakers see US economy rapidly losing momentum.
Trade worries too added to the uncertainty. While US trade delegates head to Beijing next week, President Donald Trump said a final agreement with China "will probably happen."
Chipmakers, which get a huge chunk of their revenue from China, fell. The Philadelphia chip index was down 2.29 percent, while the broader technology sector declined 1.64 percent.
At 12:44 p.m. ET the Dow Jones Industrial Average was down 449.97 points, or 1.73 percent, at 25,512.54. The S&P 500 was down 52.68 points, or 1.85 percent, at 2,802.20 and the Nasdaq Composite was down 175.96 points, or 2.24 percent, at 7,663.00.