sunk costs

In economics and business decision-making, sunk costs are costs that cannot be recovered once they have been incurred. Sunk costs are sometimes contrasted with variable costs, which are the costs that will change due to the proposed course of action, and prospective costs which are costs that will be incurred if an action is taken. In microeconomic theory, only variable costs are relevant to a decision. Economics proposes that a rational actor does not let sunk costs influence one's decisions, because doing so would not be assessing a decision exclusively on its own merits. The decision-maker may make rational decisions according to their own incentives; these incentives may dictate different decisions than would be dictated by efficiency or profitability, and this is considered an incentive problem and distinct from a sunk cost problem. In decision making one should also consider fixed proportion of the sunk costs. Lets take an example of a market which has a free entry. There are several firms in the market operating profitably, but if high proprotions of sunk cost in this market are fixed costs then others firms would hesitate to enter into that market while on the other hand if very low proportion of sunk cost are fixed costs for the same market, firms would love to enter into that market.