'Shadow' inventory may slow housing recovery

The housing market has shown some signs of life recently. Existing home sales are up, prompting some optimism. But at the same time, an untold number of houses that have yet to hit the market are waiting in the wings. And the bigger that so-called shadow inventory, the further off the housing recovery might be. By the official count, about 3.5 million homes are on the market right now. Given the rate of home sales, that's roughly twice the normal supply. But "that could just be the tip of the iceberg," says Stan Humphries, chief economist for the real estate Web site Zillow. It's not what is already for sale that worries economists like him; it's the number of homes that might hit the market in the months to come.