So, what is the catch to the HUD REO 100 Down Mortgage? The only catch is the property must be a HUD owned home. Basically, a HUD home is a home that was foreclosed on and had an FHA-insured mortgage. HUD pays off the losses of the bank or lender and takes the home back to sell, thus recouping their losses. It is then offered for sale at market value, based on a recent AS-IS appraisal, meaning, and the market value in its current condition. If you find a HUD home you like, a HUD registered realtor is needed to help set up a showing and to make a bid. HUD homes are listed for sale by management companies under contract by HUD.