Reasons to short
The growth of the mortgage industry was fueled by cheap credit.The interest rates were so low that financial firms were finding it difficult to get good returns.And the person on the street was not getting returns for being frugal and saving money.The savings accounts paid too little.This caused a shift in money into other asset classes like stocks and real estate.As a result we had a boom in both asset classes.As a result people began to feel wealthy.And prices were coming down because they were being manufactured in low cost countries like China.The banks in their quest for higher returns encouraged people to borrow.And so they did.With every bubble we have excesses.Enter subprime and ninja loans.And what is worse is that even now corrective steps are not being taken.Interest rates are still negative.A decade of mismanagement will not be unwound in a year or two.There is a long long way to go on the downside.Of course there will be sucker rallies when people pile in to buy thinking that a bottom has been reached.But unemployment is still too low.People will find difficulty in feeding themselves as commodity prices kick in fully.That would push disposable income lower.This is coming at a time when mortgage rates are going to go up.So I do not see any reason why the housing market is going to recover anytime soon.
http://en.wikipedia.org/wiki/Real_estate_bubble