Updated from 4:08 p.m. EDT

Stocks slid hard Tuesday as new worries about the credit arena and a profit shortfall at DuPont ( DD) overshadowed another round of mostly solid earnings reports elsewhere.

The Dow Jones Industrial Average lost 226.47 points, or 1.62%, to 13,716.95. The S&P 500 fell 30.53 points, or 1.98%, to 1511.04, and the Nasdaq plunged 50.72 points, or 1.89%, to 2639.86.

Traders were focusing on the negatives, including the fact that DuPont, a component of the Dow, missed second-quarter expectations. The chemicals concern kept its full-year forecast, but shares slid $3.36, or 6.3%, to end at $49.90.

A disappointment from Texas Instruments ( TXN), which reported after the previous close, hit tech stocks. The chipmaker said its second-quarter earnings were in line with consensus targets but down from a year ago, and its sales outlook was on the light side. TI fell $1.72, or 4.5%, to $36.46.

Weighing further on the market were renewed concerns about debt, which have popped up several times in recent months. After the previous close, American Express ( AXP) topped analysts' profit estimates, but the financial services giant said it had to increase its loan-loss reserve because of a higher rate of delinquencies.

The Dow component's stock lost $3.49, or 5.4%, to close at $61.17.

Meanwhile, lender Countrywide ( CFC) missed by a wide margin, citing increased credit-related costs, and lowered its 2007 guidance, saying the second half will be challenging. It also said liquidity for mortgage securities has been reduced. Shares of Countrywide tumbled $3.56, or 10.5%, to $30.50.

"There's fear entering certain parts of the market, and we're seeing a risk adjustment taking place," said Paul Mendelsohn, chief investment strategist with Windham Financial. "This shift could be foreshadowing something bigger, as everyone could run for the door at the same time. Once markets start picking up momentum, they tend to keep moving because everyone's on the same side."

Virtually every sector finished with losses. Among the worst decliners, the Amex Oil Index dropped 3.5%, the Philadelphia Utility Index slumped 3.5%, the Nasdaq Financial Index fell 3%, and the KBW Bank Index lost 3%.

Apple ( AAPL), which will post earnings late Wednesday, contributed to the tech sector's slide amid speculation the iPhone maker will miss sales targets for the new gadget. Shares tumbled 6.1% to $134.89.

Trading curbs were put into effect on the New York Stock Exchange for the first time since March 13, when subprime fears surrounding New Century ( NEWCQ) and Accredited Home Lenders ( LEND) first became a force and sank the major averages.

About 3.91 billion shares changed hands on the NYSE, as decliners toppled advancers by a 9-to-1 margin. Volume on the Nasdaq reached 2.46 billion shares, with losers outpacing advancers 5 to 1.

Another setback came from General Motors ( GM), which, according to a report in The Wall Street Journal, is having trouble raising debt for its Allison engine unit. The division is trying to raise funds to complete a leveraged buyout. GM shed 47 cents, or 1.3%, to $34.65.

However, it wasn't all bad, despite the pullback. AT&T ( T) was better than expected on the profit line, as were Lockheed Martin ( LMT) and CME ( CME). While AT&T and CME declined, Lockheed Martin shot higher by 3.6% to $103.09.

British oil major BP ( BP) said earnings rose 1.5%, and Eli Lilly ( LLY) exceeded estimates and lifted its projections. BP dipped 2.9% to $72.30, while Eli Lilly finished the day unchanged at $57.17.

Pepsi ( PEP), EMC ( EMC) and McGraw-Hill ( MHP) were also better than expected, as were UAL ( UAUA) and Northrop Grumman ( NOC). UAL was the only name in the group to finish with gains, ending higher by 4.2% for the session.

Dow stock McDonald's ( MCD) posted only its second-ever quarterly loss. Excluding items, the restaurant chain matched the forecast for a profit of 71 cents a share. Shares slipped 95 cents, or 1.8%, to finish at $51.55.

On the research front, Citigroup upgraded Wachovia ( WB) to buy from hold, citing valuation. Still, shares closed lower by 41 cents, or 0.8%, to $48.41.

Among downgrades, Jefferies cut both United Rentals ( URI) and GlobalSantaFe ( GSF) to hold from buy. United Rentals was off by 56 cents, or 1.7%, to $32.42. GlobalSantaFe ended down 73 cents, or 0.9%, to $77.60.

On Monday, both stocks made M&A headlines and gave the major averages a boost. Transocean ( RIG) said it will combine with GlobalSantaFe to form a driller with an enterprise value of $53 billion. Private-equity firm Cerberus said it will acquire United Rentals for $2.83 billion.

Away from stocks, the front-month September crude contract sank for a second session. Oil dropped $1.33 to $73.56 a barrel. Gasoline prices were lower by 5 cents at $2.05 a gallon.

"Because oil prices were down so much today, a lot of oil stocks were under pressure," said Mendelsohn. "There is no sector to pick up the slack today. Unless something causes the financial sector to bottom, I don't see any other sector big enough to pick up the slack and carry this market."

With the economic docket vacant, Treasury prices were little changed. The 10-year note tacked on 2/32 in price, yielding 4.95%, and the 30-year bond was flat, yielding 5.06%.

Overseas, stocks rose in Asia and declined in Europe. Tokyo's Nikkei added 0.2%, and Hong Kong's Hang Seng climbed 0.5%. London's FTSE shed 1.9%, and Frankfurt's DAX was off 1.7%.

Following Tuesday's close, Amazon.com ( AMZN) and homebuilder Centex ( CTX) will post quarterly results.

The earnings torrent will continue before the next open, when such names as Boeing ( BA), ConocoPhillips ( COP), Corning ( GLW), and WellPoint ( WLP) are due to report.

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