Stock index futures pointed to a mixed open on Wednesday as General Motors inched closer to bankruptcy and investors await a key report on the housing market.

Sales of existing homes are expected to have risen at an annual rate of 4.66 million units, according to the median forecast of 66 economists polled by Reuters, as low interest rates, low home prices and government stimulus stir buying interest. The report is due at 10 a.m.

General Motors Corp shares slumped 10.4 percent to $1.29 in premarket trade as the largest U.S. automaker prepared for the fallout from a failed debt exchange which pushes the company closer to a bankruptcy filing expected by the end of the month.

I think housing continues to be an overhang and until housing gets better and job numbers get better, we're still in a struggling economy, said Warren Simpson, managing director at Stephens Capital Management in Little Rock, Arkansas.

Obviously things are a little better, leading indicators are better, but we're not out of the woods yet.

S&P 500 futures fell 1 point and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones Industrial Average futures shed 6 points, while Nasdaq 100 futures were off 4.25 points.

Bank of America Corp shares rose 2.3 percent to $11.23 after the company said that it has raised $26 billion in its capital plan to date. The Federal Reserve had set a $33.9 billion buffer for the bank under its stress test.

Staples slipped 2.9 percent to $19.80 in premarket trade after the office products retailer reported adjusted first-quarter earnings that were a penny above Wall Street forecasts, boosted by cost savings in its Corporate Express unit.

Monsanto Co shares fell 4.1 percent to $81.80 after the agricultural products maker said that it was on track to meet the lower end of its prior fiscal year 2009 guidance.

Through Tuesday, 97 percent of S&P 500 companies had reported earnings, with 65 percent topping Wall Street estimates.

Also on the housing front, the Mortgage Bankers Association said that the highest home loan rates in more than two months drained demand for refinancing last week, dragging total U.S. mortgage applications to the lowest level since early march.

U.S. stocks climbed more than 2 percent on Tuesday as data showing the biggest monthly jump in consumer confidence in six years lifted hopes of an economic rebound while a brokerage upgrade of Apple Inc drove sharp gains on the Nasdaq.

Tuesday's gains enabled the blue-chip Dow to reclaim nearly 90 percent of its declines from the previous four sessions.

Since reaching a low in early March, the Dow has gained more than 29 percent and the S&P 500 has risen nearly 35 percent.

Investment