Markets can differ by products (goods, services) or factors (labour and capital) sold, product differentiation, place in which exchanges are carried, buyers targeted, duration, selling process, government regulation, taxes, subsidies, minimum wages, price ceilings, legality of exchange, liquidity, intensity of speculation, size, concentration, exchange asymmetry, relative prices, volatility and geographic extension. The geographic boundaries of a market may vary considerably, for example the food market in a single building, the real estate market in a local city, the consumer market in an entire country, or the economy of an international trade bloc where the same rules apply throughout. Markets can also be worldwide, see for example the global diamond trade. National economies can also be classified as developed markets or developing markets.
In mainstream economics, the concept of a market is any structure that allows buyers and sellers to exchange any type of goods, services and information. The exchange of goods or services, with or without money, is a transaction. Market participants consist of all the buyers and sellers of a good who influence its price, which is a major topic of study of economics and has given rise to several theories and models concerning the basic market forces of supply and demand. A major topic of debate is how much a given market can be considered to be a 'free market', that is free from government intervention. Microeconomics traditionally focuses on the study of market structure and the efficiency of market equilibrium; when the latter (if it exists) is not efficient, then economists say that a market failure has occurred. However, it is not always clear how the allocation of resources can be improved since there is always the possibility of government failure.