Wall Street has extended last week's slide on worries that the quarterly results companies begin releasing this week will signal the economy is in worse shape than feared.
Oil prices have tumbled 8 percent Monday to a new low for the year as investors have bet economic weakness will curb demand. That assessment is reinforcing fears that a slowing economy will further erode corporate profits.
The Dow Jones industrial average is ending down 125, or 1.5 percent, at the 8,474 level. Broader indexes fell more than 2 percent.