Current residential shadow inventory as of October 2011 remained at 1.6 million units – representing a supply of five months – down from a seven-month supply of 1.9 million units one year earlier, according to CoreLogic. It’s the same level reported in July 2011.

Currently, the flow of new seriously delinquent loans into the shadow inventory has been offset by the roughly equal flow of distressed (short and real estate owned) sales.

CoreLogic estimates the shadow inventory, also known as pending supply, based on the number of distressed properties not currently listed on multiple listing services (MLSs) that are seriously delinquent (90 days or more) – properties most likely to become bank-owned listings (REOs). Properties not yet delinquent aren’t included in the estimate of shadow inventory.

Data highlights:

* As of October 2011, shadow inventory remained at 1.6 million units, or 5-months’ supply and represented half of the 3 million properties currently seriously delinquent, in foreclosure or in REO.

* Of the 1.6 million properties currently in the shadow inventory, 770,000 units are seriously delinquent (2.5-months’ supply), 430,000 are in some stage of foreclosure (1.4-months’ supply) and 370,000 are already in REO (1.2-months’ supply).

* Florida, California and Illinois account for more than a third of the shadow inventory. The top six states, which would also include New York, Texas and New Jersey, account for half of the shadow inventory.

* Despite 3 million distressed sales since January 2009, a period when home prices were declining at their fastest rate, the shadow inventory in October 2011 is at the same level as January 2009.

* Because shadow inventory is often concentrated in suburban and exurban submarkets, where distressed sales compete with new construction sales, it is one of the reasons why new home sales continue to be weak. In normal times, new home sales account for 12 percent of all sales, but they are currently running at 7 percent of all sales.

“The shadow inventory overhang is a large impediment to the improvement in the housing market because it puts downward pressure on home prices, which hurts home sales and building activity while encouraging strategic defaults,” said Mark Fleming, chief economist for CoreLogic.