section_path: Microeconomics/Firms
section_name: Firms
paragraph_text: Firms
  
  People frequently do not trade directly on markets. Instead, on the supply side, they may work in 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. Firms combine labour and capital, and can achieve far greater economies of scale (when the average cost per unit declines as more units are produced) than individual market trading.
  
  In perfectly competitive markets studied in the theory of supply and demand, there are many producers, none of which significantly influence price. Industrial organisation generalises from that special case to study the strategic behaviour of firms that do have significant control of price. It considers the structure of such markets and their interactions. Common market structures studied besides perfect competition include monopolistic competition, various forms of oligopoly, and monopoly.
  
  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 optimise business decisions, including unit-cost minimisation and profit maximisation, given the firm's objectives and constraints imposed by technology and market conditions.