PORTLAND — Portland-area lenders have been reluctant to release their shadow inventory of repossessed homes.

More than 80 percent of the repossessed homes in the Portland area are off the market.

In some cases, particularly after the robo-signing scandal, lenders had paperwork issues to resolve before they could sell condos and houses. But at least part of the delay is likely a bookkeeping maneuver because the repossessed homes haven’t been marked down to their new market value.

“The banks are going to have to take a loss at the time of the sale,” said Rick Sharga, executive vice president of Carrington Mortgage Holdings. “One way of managing those losses is to sort of delay the process a little bit.”

Another reason to delay selling the backlog is because home prices might crumble if a wave of properties hits the market at the same time. On the other hand, homes left sitting vacant for too long might develop maintenance problems that hurt their eventual resale value.

The issue of shadow inventory is statewide. Oregon has a 19-month supply of bank-owned homes at their current rate of sale, said Daren Blomquist, vice president of RealtyTrac. Brokers contend that the rate of sale is constrained by the number of houses banks are releasing, not the number the market will bear.

“My goodness, we would sell the daylights out of these properties right now,” said Don McCredie, a principal broker with Realty Trust Group in Lake Oswego.