The Nasdaq Composite index was set to drop more than 1 percent at the open.
Wachovia Corp said it had incurred about $1.1 billion of losses on mortgage securities in October and expected loan loss provisions of up to $600 million, further reducing earnings.
The U.S. bank's news came as shares of Barclays Plc slid in Europe on market talk of a $10 billion write-down at Britain's third-biggest bank. A Barclays spokesman denied the rumors, but the stock still was down about 5 percent.
S&P 500 futures fell 14.9 points and were below fair value, a formula to evaluate pricing taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures dropped 100 points, and Nasdaq 100 futures slid 30.5 points.