U.S. stocks declined on Friday, with benchmark indexes headed for sizable weekly losses, as crude's ongoing slide rattled investors.
The Chicago Board Options Exchange Volatility Index, one measure of investor uncertainty, rose 1.2 percent to 20.32, up 72 percent this week.
Oil prices fell further after the International Energy Agency reduced its outlook for global demand.
Equities around the globe dropped on Friday after November Chinese factory production slowed more than forecast.
U.S. wholesale prices declined 0.2 percent drop in the producer price index in November after a 0.2 percent rise the previous month.
Adobe Systems gained after the software maker said it would acquire stock-photo company Fotalia for $800 million and posted quarterly results that beat expectations.
Stocks only briefly trimmed losses after a measure of consumer sentiment in December exceeded expectations, rising to an eight-year high.
After a 284-point fall, the Dow Jones Industrial Average was lately down 299.23 points, or 1.7 percent, to 17,297.11, with International Business Machines leading blue-chip losses that extended to 28 of 30 components.
The S&P 500 shed 32.66 points, or 1.7 percent, to 2,002.64, with materials falling the most among its 10 major industry groups, with all in negative terrain.
The Nasdaq declined 54.57 points, or 1.16 percent, to 4,653.60.
For every share rising, three fell on the New York Stock Exchange, where 627 million shares traded as of 3:45 p.m. Eastern. Composite volume neared 3.4 billion.
The U.S. dollar declined against the currencies of major U.S. trading partners and dollar-denominated commodities including gold and oil fell.
Crude futures for January delivery declined $2.14, or 3.6 percent, to $57.84 a barrel, settling below $58 a barrel for the first time since May 2009. The February gold contract fell $3.10, or 0.3 percent, to $1,222.50 an ounce on the New York Mercantile Exchange.
The yield on the 10 year Treasury note used to figure mortgage rates and other consumer loans dropped 7 basis points to 2.0984 percent.
The scariest part of today is that the markets were falling as the trading day was closing. At least we have the weekend to sort things out.