First American CoreLogic estimates a 1.7m pending supply of homes was ready to hit the market as of September 2009. First American CoreLogic is the property and ownership information provider subsidiary of The First American Corp. (FAF). Also known as the “shadow inventory," these homes are either in serious delinquency or in the foreclosure process. This new estimate from First American is up from 1.1m from a year ago. At the current sales rate, it will take 3.3 months to run through the supply, up from 2.4 months last year. The amount of new and existing homes currently on the market reached 3.8m, a drop from 4.7m a year ago. At the current sales rate, it would take 7.8 months to move through the existing inventory, dropping from 10.1 months a year earlier. Combined, the pending and existing supply of homes reached 5.5m homes in September, down from 5.7m a year ago, and it would take 11.1 months to move through the inventory. That’s down from 12.7 months last year. According to the report, this indicates that while the existing supply has dropped and is about to approach normal levels, the injection of pending inventory will affect the housing market for the next few years. What matters is how this pending inventory will hit the market. Unless banks disberse the “shadow inventory” onto the market in a controlled and measured rate, housing prices could double-dip again in 2010. Write to Jon Prior.