More signs of distress in China's economy and rising U.S. bond yields are weighing on U.S. stocks in early trading.
The Dow Jones industrial average fell 160 points, or 1.1 percent, to 14,639 in the first few minutes of trading Monday.
The Standard & Poor's index fell 24 points, or 1.2 percent, to 1,570. The Nasdaq composite fell 45 points, or 1.3 percent, to 3,312.
An increase in China's commercial lending rates brought new worries about China's finances. China's Shanghai Composite Index plunged 5 percent, its biggest loss in four years.
The selling also spread to Europe. France's index fell 1.8 percent, Germany's 1.2 percent.
In the U.S., the yield on the 10-year Treasury note jumped to 2.62 percent from 2.54 Friday, its highest level in almost two years.