NEW YORK (CNN/Money) - Warnings from Dow Jones industrial average component DuPont and Siemens, combined with continued concerns about Citigroup and J.P. Morgan's Enron transactions, soured investor sentiment Wednesday, pointing to a lower opening for stock markets.

Nasdaq-100 and Standard & Poor's futures were sharply lower, indicating a selloff at the start of trading.

Chemical maker DuPont (DD: up $0.26 to $37.08, Research, Estimates) posted sharply improved earnings that beat Wall Street's expectations for the period, but the company warned that it expects third-quarter results below current forecasts.

This extended losses in the futures that appeared after Siemens issued a warning for its fiscal fourth quarter, although it posted better-than-expected results for the third quarter. The news sent European markets stumbling in midday trading.

"Europe is having an absolutely horrendous day. We've had very bad results, Siemens warning, concerns about the banks' exposure to Enron," said Tamzin Hobday, analyst with WestLB Panmure in London. "With confidence being as shattered as it is at the moment, people are getting very, very nervous."

"But I think we're going to see recovery in the next couple of days. It'll be very volatile until we get this results season out of the way," Hobday added. "We need to see capital expenditure picking up in the U.S. right across the board to see any real recovery."

Asian markets had already sold off, responding to the big drop in U.S. markets on Tuesday. Tokyo's Nikkei index fell 2.6 percent to finish below 10,000 for the first time since February.

Concern about financial services companies highlighted the U.S. declines as Citigroup (C: Research, Estimates) and J.P. Morgan Chase (JPM: Research, Estimates) were accused at a Senate hearing of helping bankrupt energy trader Enron obfuscate its financial statements. The Dow Jones industrial average fell another 1 percent, retreating to another four-year low; the Nasdaq slumped 4 percent on weakness in semiconductor issues (see chart).

Dow component McDonald's (MCD: Research, Estimates), the fast-food purveyor, posted a second-quarter operating profit of 39 cents a share, up from 34 cents in the second quarter of 2002 and above the consensus forecast of 38 cents.

After trading concludes, media company AOL Time Warner (AOL: Research, Estimates) issues its second-quarter results, following its recent management shakeup. The company, parent of CNN/Money, is forecast to report profit of 22 cents a share, down from 32 cents a year earlier.

Treasury prices soared, sending the 10-year note yield down to 4.24 percent from 4.47 percent late Tuesday. The dollar weakened against the yen and euro, which remained below $1.

Brent oil futures added 23 cents to $25.27 a barrel in London, where gold slipped in early trading.

Late Tuesday, online retailer Amazon.com (AMZN: Research, Estimates) reported a narrower-than-expected second-quarter loss, forecast an operating profit for 2002, and said it would start to account for stock options as an expense. The company's European shares fell 11 percent in early trading. Credit Suisse First Boston raised its third quarter and 2002 estimates for Amazon, with a "buy" rating on the stock. Amazon shares lost $1.75 to $12.80 before hours.

WR Hambrecht downgraded AT&T Wireless (AWE: Research, Estimates) to "market perform" from a "buy," a day after the nation's No. 3 wireless telephone company posted second-quarter results that matched Wall Street expectations but cut its target for new customers in 2002 to 2 million to 2.2 million. AT&T Wireless also said customer additions in the third quarter will be significantly lower than the second quarter and "the low watermark for the year," blaming an industry-wide slowdown in customer growth and increased competition.

AT&T Wireless shed 55 cents to $5.35 Tuesday.

Merrill Lynch upgraded Anadarko Petroleum (APC: Research, Estimates), the natural gas and oil exploration and production firm, to "strong buy," pointing out that the stock is down 33 percent year-to-date and that it does not see much downside to the stock in the near term. Anadarko shares dropped $1.29 to $38 Tuesday.

Merrill downgraded Textron (TXT: Research, Estimates), the global multi-industry company and the maker of Cessna airplanes, to "neutral" from "strong buy" and also cut its 2002 and 2003 estimates on the stock, saying in a note that despite of a 30 percent price drop since mid-April, "Textron shares have significantly outperformed the market along with many large industrial companies. However, we see a very limited benefit from a cyclical recovery at Textron."

Textron shares shed 9 cents to $36.32 Tuesday.

Credit Suisse First Boston downgraded satellite radio broadcaster XM Satellite Radio Holdings (XMSR: Research, Estimates) to "hold" from "buy," a day after it posted a wider second-quarter loss. The brokerage also trimmed its 2002 and 2003 estimates on Lucent Technologies (LU: Research, Estimates) after the troubled telecom equipment maker on Tuesday reported unexpectedly poor results in its fiscal third quarter. XM Satellite dropped $1.25 to $4, while Lucent lost 45 cents to $1.65 Tuesday.

Expedia (EXPE: Research, Estimates) on Tuesday reported second-quarter earnings which met Wall Street expectations, but the stock fell $6.76 to $41.65 before hours on uncertainty about a bid from USA Interactive (USAI: Research, Estimates) to buy out three of its majority-owned units.