NEW YORK (MarketWatch) -- U.S. stocks fell at Tuesday's start, with the technology sector especially hammered by earnings reports that came in under expectations and pessimistic forecasts from the likes of chip maker Texas Instruments Inc. and chemical giant DuPont.
"The real problem is not so much the earnings themselves, but the guidance, which is murky," said Peter Cardillo, chief market economist at Avalon Partners.
The Dow Jones Industrial Average fell 191 points to 9,126.
In addition to information technology, energy proved the hardest hit sector, with oil giants and Dow components Exxon Mobil Corp. and Chevron Corp. both down about 3% as crude futures fell to under $72 a barrel.
Shares of Caterpillar Inc. fell 1.5% after the heavy-equipment maker reported a third-quarter profit decline of 6% from the year-ago period, but held firm to its previous target of $6 a share profit for 2008.
American Express Co. fell 0.7% after it reported a smaller-than-forecast 24% profit fall for the third quarter late on Monday.
DuPont slipped 3.5% after cutting its earnings outlook.
Pfizer rose 2.4% after tripling its third-quarter profit. Also on the rise, 3M shares advanced after the diversified industrial behemoth reported a third-quarter profit gain of 3.2%. .
The S&P 500 fell 13.03 points to 972.37 and the Nasdaq Composite declined 28.97 points to 1,741.07.
Gloomy outlooks pressured Texas Instruments , its shares dropping 11.6%.
Sun Microsystems Inc. dropped 13.7% as the network server firm forecast a bigger loss than analysts had anticipated.
After the close, Yahoo Inc. and Apple Inc. are scheduled to report results, with expectations that Yahoo will announce job cuts.
On Monday, U.S. equities surged after a key inter-bank lending rate dropped and after Federal Reserve Chairman Ben Bernanke endorsed a second stimulus package. The Dow Jones Industrial Average rocketed 411 points, the S&P 500 added 44 points and the Nasdaq Composite climbed 58 points.
By Kate Gibson