US stocks tumbled Friday, and bond yields continued to climb amid new warnings on the global economy. 

The Dow shed more than 300 points, and major indexes are facing their fourth losing session in a row. S&P Global's Purchasing Managers' Index — a broad gauge of economic health — plummeted to 48.2 in September from 48.9 last month, showing that business activity continues to shrink. 

Stocks are set for a losing week after the Federal Reserve and a plethora of other central banks made policy adjustments to curb inflation. Goldman Sachs slashed its year-end forecast for the S&P 500, and warned that the Fed's aggressive policy path would lead to further sell-offs in stocks. 

"The expected path of interest rates is now higher than we previously assumed, which tilts the distribution of equity market outcomes below our prior forecast," the bank's strategists wrote in a Thursday note.

Here's where US indexes stood as the market opened at 9:30 a.m. on Friday: 

• S&P 500: 3,713.44, down 1.19%

• Dow Jones Industrial Average: 29,755.54, down 1.07% (321.14 points)

• Nasdaq Composite: 10,932.10, down 1.22%

Here's what else is happening today: 

In commodities, bonds, and crypto:

• Oil prices plunged, with West Texas Intermediate down 4.48% to $79.74 a barrel. Brent crude, the international benchmark, shed 3.89% to $86.98 a barrel.
• Gold shed 1.02% to $1,664.42 per ounce.
• The 10-year yield ticked higher by 0.9 basis points to 3.699%.
• Bitcoin slipped  1.56% to $19,031.25.