Firms

One of the assumptions of perfectly competitive markets is that there are many producers, none of whom can influence prices or act independently of market forces. In reality, however, people do not simply trade on markets, they work and produce through firms. The most obvious kinds of firms are corporations, partnerships and trusts. According to Ronald Coase people begin to organise their production in firms when the costs of doing business becomes lower than doing it on the market.^[72] Firms combine labour and capital, and can achieve far greater economies of scale (when producing two or more things is cheaper than one thing) than individual market trading.

Labour economics seeks to understand the functioning of the market and dynamics for labour. Labour markets function through the interaction of workers and employers. Labour economics looks at the suppliers of labour services (workers), the demanders of labour services (employers), and attempts to understand the resulting patterns of wages and other labour income and of employment and unemployment, Practical uses include assisting the formulation of full employment of policies.^[73]

Industrial organization studies the strategic behavior of firms, the structure of markets and their interactions. The common market structures studied include perfect competition, monopolistic competition, various forms of oligopoly, and monopoly.^[74]

Financial economics, often simply referred to as finance, is concerned with the allocation of financial resources in an uncertain (or risky) environment. Thus, its focus is on the operation of financial markets, the pricing of financial instruments, and the financial structure of companies.^[75]

Managerial economics applies microeconomic analysis to specific decisions in business firms or other management units. It draws heavily from quantitative methods such as operations research and programming and from statistical methods such as regression analysis in the absence of certainty and perfect knowledge. A unifying theme is the attempt to optimize business decisions, including unit-cost minimization and profit maximization, given the firm's objectives and constraints imposed by technology and market conditions.^[76][77]

Public sector

Public finance is the field of economics that deals with budgeting the revenues and expenditures of a public sector entity, usually government. The subject addresses such matters as tax incidence (who really pays a particular tax), cost-benefit analysis of government programs, effects on economic efficiency and income distribution of different kinds of spending and taxes, and fiscal politics. The latter, an aspect of public choice theory, models public-sector behavior analogously to microeconomics, involving interactions of self-interested voters, politicians, and bureaucrats.^[78]

Much of economics is positive, seeking to describe and predict economic phenomena. Normative economics seeks to identify what is economically good and bad.

Welfare economics is a normative branch of economics that uses microeconomic techniques to simultaneously determine the allocative efficiency within an economy and the income distribution associated with it. It attempts to measure social welfare by examining the economic activities of the individuals that comprise society.^[79]