When a property owner fails to make their mortgage payments for a number of months they are in default. The first step of the foreclosure process (which typically takes a number of months) that the lender will take is to file the notice of default. This is a public document that is recorded. The property owner will contract to sell the home conditioned upon the lender accepting a lesser amount than what is owed on the mortgage. Note that there are no similarities between a real estate short sale and selling a stock short.