The goods traded on the market must be completely identical, which means that they must not have any differences in quality, color, dimensions, taste, pattern, etc. It is said that the goods must be "homogeneous". (Examples: banknotes, shares of a certain stock company, precious metals, cotton of a certain standard).
Buyers and sellers are not allowed to prefer each other, which means that there are no “personal preferences”. Such preferences arise z. B. through particularly courteous service in certain shops.
supply and demand müssen an einem bestimmten Ort zusammentreffen (Punktmarkt). Dies ist beispielsweise bei Wochenmärkten, Messen, Auktionen, Versteigerungen oder den Börsen der Fall. Es dürfen also keine räumlichen Präferenzen bestehen.
Supply and demand must meet at the same time, i.e. they must not be differentiated over time. In most consumer and capital goods markets, this condition does not apply because buyers and suppliers appear on the markets at very different times.
A complete overview of the market must be given for suppliers and customers, which means that the suppliers must be informed about which quantities and at what prices the customers want to buy, the customers about which quantities and at what prices the providers want to sell. These conditions of so-called market transparency are most likely still applicable to stock exchanges.
Suppliers and buyers must be able to react immediately to changes (infinitely fast reactivity). In most cases, however, this condition does not exist. Increases z. For example, if there is demand for beef, farmers cannot immediately increase their supply to the extent necessary. Rather, they have to wait until the offspring are ready for slaughter before increasing the supply.