Capital gain is an increase in the value of a capital asset (investment or real estate) that gives it a higher worth than the purchase price. The gain is not realized until the asset is sold. A capital gain may be short-term (one year or less) or long-term (more than one year) and must be claimed on income taxes.
Pure or perfect competition is a theoretical market structure in which the following criteria are met: all firms sell an identical product (the product is a "commodity" or "homogeneous"); all firms are price takers (they cannot influence the market price of their product); market share has no influence on price; buyers have complete or "perfect" information – in the past, present and future – about the product being sold and the prices charged by each firm; resources such as labor are perfectly mobile; and firms can enter or exit the market without cost.