Bank woes bring out the bears

NEW YORK (CNNMoney.com) -- U.S. stock futures were weaker Wednesday, as a bigger-than-expected writedown of assets at No. 1 brokerage firm Merrill Lynch again brought attention to problems in the credit markets.

Merrill (Charts, Fortune 500) reported a net loss of $2.82 a share, as it said that it was taking a $7.9 billion writedown of its assets. That's far worse than the $4.5 billion to $5 billion writedown that it had previously signaled and even worse than the $7 billion to $7.5 billion writedown reported earlier Wednesday by the Wall Street Journal and New York Times.

In the tech sector, Amazon.com (Charts, Fortune 500) reported late Tuesday a surge in quarterly sales and earnings. But investors expressed disappointment with the results, sending the online retailer's shares lower in after-hours trading.

But there was positive earnings news from Dow component Boeing (Charts, Fortune 500). The aircraft maker posted improved earnings that beat forecasts, as it raised its earnings and revenue guidance for 2007 - although it also gave details about how the previously announced delays in the 787 would hit 2008 results.

While futures remained in negative territory, they ticked up slightly following the Boeing report.

Leading home builder Pulte Homes (Charts, Fortune 500) is due to report results after the close, and it's projected to report a large loss.

Another look at the battered housing sector will come at 10 a.m. ET from the National Association of Realtors, which is due to report on existing home sales for September. Economists surveyed by Briefing.com are forecasting that the pace of sales fell to at least a six-year low in the period, and further declines in prices are likely.

In other corporate news, Google (Charts, Fortune 500) made a new push to sell more television ads, announcing it will pay rating service Nielsen an undisclosed amount to obtain detailed information about the kinds of people who watch specific TV shows.

Oil prices fell to near the $85 a barrel mark in early trading ahead of the 10:30 a.m. ET weekly report on U.S. fuel inventories.

In global trade, stocks in Asia gave up their gains and European markets were lower in early trading.