Companies do not make any economic profits in a
perfectly competitive market once it has reached a
long run equilibrium. If an economic profit was available, there would be an incentive for new firms to enter the industry, aided by a lack of
barriers to entry, until it no longer existed. When new firms enter the market, the overall supply increases. Furthermore, these intruders are forced to offer their product at a lower price to entice consumers to buy the additional supply they have created and to compete with the incumbent firms (see ). they are also forced to reduce their prices. Therefore, increased competition reduces price and cost to the minimum of the long run average costs. At this point, price equals both the marginal cost and the average total cost for each good production. When this occurs, economic agents outside the industry find no advantage to entering the market, as there is no economic profit to be gained. Then, the supply of the product stops increasing, and the price charged for the product stabilizes, settling into an
equilibrium. The same is likewise true of the
long run equilibria of
monopolistically competitive industries, and more generally any market which is held to be
contestable. Normally, a firm that introduces a differentiated product can initially secure
temporary market power for a
short while (See
Monopoly Profit § Persistence). At this stage, the initial price the consumer must pay for the product is high, and the demand for, as well as the
availability of the product in the market, will be limited. In the long run however, when the profitability of the product is well established, and because there are few
barriers to entry, the number of firms that produce this product will increase. Eventually, the supply of the product will become relatively large, and the price of the product will reduce to the level of the average cost of production. When this finally occurs, all economic profit associated with producing and selling the product disappears, and the initial monopoly turns into a competitive industry. In the case of contestable markets, the cycle is often ended with the departure of the former "hit and run" entrants to the market, returning the industry to its previous state, just with a lower price and no economic profit for the incumbent firms. Economic profit can, however, occur in competitive and contestable markets in the short run, since short run economic profits attract new competitors and prices fall. Economic loss forces firms out of the industry and prices rise till marginal revenue equals marginal cost, then reach long run equilibrium. As a result of firms jostling for market position. Once risk is accounted for, long-lasting economic profit in a competitive market is thus viewed as the result of constant cost-cutting and performance improvement ahead of industry competitors, allowing costs to be below the market-set price. == Uncompetitive markets ==