The BauGB defines the Verkehrswert or Marktwert (market value, both terms with identical meaning) as follows: "The market value is determined by the price that can be realized at the date of valuation, in an arm's length transaction, with due regard to the legal situation and the effective characteristics, the nature and lay of the premises or any other subject of the valuation" (non-official translation). The intention, as in other countries, is to include all objective influences and to exclude all influences resulting from the subjective circumstances of the involved parties.
These appraisers also perform valuations on commercial property ranging from single to multiple tenant office buildings, shopping centers, retail, industrial, malls, hospitals, health care facilities, warehouses, and hotels to multi-family apartment buildings, co-ops, senior housing, condominium developments, and even vacant land, agricultural, and golf courses. Regardless of the property type or local zoning, they'll determine the highest and best use of the project and assess the value using the actual or projected cash flow from the property's rent roll and financial statements, using both cap rates for capitalizing year one net operating income (NOI) and discounted cash flow (DCF) of multiple future income streams. If you're a commercial lender, investor, builder, contractor, architect, or agent, you'll want to use these appraisers to conduct a feasibility analysis of any income producing real estate project you may be considering. They can also help consult on construction costs and projected absorption rates. They generally produce a commercial narrative appraisal when engaged for any commercial assignment.