You're thinking of the practice of shorting stocks, which is different than a short sale. From Wikipedia: A short sale is a sale of real estate in which the ne

You're thinking of the practice of shorting stocks, which is different than a short sale. From Wikipedia: A short sale is a sale of real estate in which the net proceeds from selling the property will fall short of the debts secured by liens against the property. In this case, if all lien holders agree to accept less than the amount owed on the debt, a sale of the property can be accomplished.