Appraisals are usually performed under some set of assumptions about transactional markets, and those assumptions are captured in the definition of value used for the appraisal. Commonly, the definition set forth for U.S. federally regulated lending institutions is used, although other definitions may also be used under some circumstances:

:"The most probable price (in terms of money) which a property should bring in a competitive and open market under all conditions requisite to a fair sale, the buyer and seller each acting prudently