In economics, imperfect competition refers to a situation where the characteristics of an economic market do not fulfil all the necessary conditions of a perfectly competitive market. Imperfect competition will cause market inefficiency when it happens, resulting in market failure. Imperfect competition is a term usually used to describe the seller's position, meaning that the level of competition between sellers falls far short of the level of competition in the market under ideal conditions. The structure of a market can significantly impact the financial performance and conduct of the firms competing within it. There is a causal relationship between structure, behaviour and performance paradigm. The characteristics of market structure can be measured by evaluating the degree of seller's market concentration to determine the nature of market competition. The degree of market power refers to the firms' ability to affect the price of a good and thus, raise the market price of the good or service above marginal cost (MC). Moreover, market structure can range from perfect competition to a pure monopoly. Monopolistic competition and oligopoly competition are the extreme conditions of market structure. Perfect competition occurs when there is intense price competition, perfect competition is a market situation and competitive outcome that economists use as a benchmark for economic welfare analysis and efficiency. In perfect competition, prices move closer to marginal cost when at least two of the three conditions—that there are many sellers in the market, that there is excess capacity, and that there are homogeneous products. Conditions of imperfect competition If ONE of the following conditions are satisfied within an economic market, the market is considered "imperfect": The market's goods and services are heterogeneous or differentiated. This means that firms can charge higher prices as their goods and services are perceived as better; The market contains ONE seller or none; There are barriers to market entry and exit. If there are barriers to market entry and exit, there may be special costs to a firm that may prevent or make it difficult for a firm to enter or exit an industry market. Additionally, if prices are different, buyers may not have the ability to easily switch suppliers and thus, suppliers cannot easily exit or enter the market; and Market firms are NOT price takers and hence, have some control over the pricing of their goods and services. Range of market structures There are FOUR broad market structures that