Jurow bases his conclusion primarily on concerns about so-called "shadow inventory"--a huge number of houses that will eventually be on the market but aren't counted in current inventory figures. For example, a large number of households are behind on their mortgages or have stopped paying their mortgages, Jurow says, but the banks have yet to foreclose. When banks are finally forced to foreclose, Jurow says, and these houses hit the market, they will cause significant additional price declines. Additionally, some homeowners who want to sell are waiting for price increases. When they finally give up and put their houses on the market, Jurow says, this will add additional supply.