A tax lien is an encumbrance placed against a property for unpaid property taxes. The transaction of selling a property cannot be completed until the tax lien is paid in full by the seller. The same tax lien also applies to property acquired during the entire life of the tax lien. If borrowers owe back property taxes, they are at risk of eventual mortgage foreclosure if the tax lien is not satisfied within a set period of time determined by the taxing agency. This gives the taxing authority the right to sell the home at an auction to an investor who is willing to pay off the tax lien, interest and penalties. This means that the investor is able to purchase the home without having to pay off the mortgage due on the house. This translates to an investor purchasing a home at a mere fraction of its actual value.