Various real estate research firms estimate that banks are sitting on hundreds of thousands of foreclosed homes that they have neither sold nor listed. If these rumors are true, and the banks brought these homes onto market, it would flood an already dismal housing market... causing prices to fall further.
From The San Francisco Chronicle:
Lenders nationwide are sitting on hundreds of thousands of foreclosed homes that they have not resold or listed for sale, according to numerous data sources. And foreclosures, which banks unload at fire-sale prices, are a major factor driving home values down.
"We believe there are in the neighborhood of 600,000 properties nationwide that banks have repossessed but not put on the market," said Rick Sharga, vice president of RealtyTrac, which compiles nationwide statistics on foreclosures. "California probably represents 80,000 of those homes. It could be disastrous if the banks suddenly flooded the market with those distressed properties. You'd have further depreciation and carnage."