Real estate appraisal, property valuation or land valuation is the process of developing an opinion of value, for real property (usually market value). Real estate transactions often require appraisals because they occur infrequently and every property is unique (especially their condition, a key factor in valuation), unlike corporate stocks, which are traded daily and are identical (thus a centralized Walrasian auction like a stock exchange is unrealistic). The location also plays a key role in valuation. However, since property cannot change location, it is often the upgrades or improvements to the home that can change its value. Appraisal reports form the basis for mortgage loans, settling estates and divorces, taxation, and so on. Sometimes an appraisal report is used to establish a sale price for a property.
Real estate appraisal in Germany is partly codified by law. The federal Baugesetzbuch (abbr. BauGB, "German statutory code on building and construction'") contains guidelines on governing authorities, defines the term market value and refers to continuative rules (chapter 3, articles 192 ff.). Each municipality (city or administrative district) must form a Gutachterausschuss (appraisal committee), consisting of a chairman and honorary members. The committee gathers information on all real estate deals (it is mandatory to send a copy of each notarial purchase contract to the Gutachterausschuss) and includes it in the Kaufpreissammlung (purchase price database). Most committees publish an official real estate market report every two years, in which besides other information on comparables the land value is determined. The committees also perform appraisals on behalf of public authorities.