In economics, a deadweight loss (also known as excess burden or allocative inefficiency) is a loss of economic efficiency that can occur when equilibrium for a good or service is not achieved or is not achievable. Causes of deadweight loss can include monopoly pricing (in the case of artificial scarcity), externalities, taxes or subsidies, and binding price ceilings or floors (including minimum wages). The term deadweight loss may also be referred to as the "excess burden" of monopoly or taxation.