Overselling
（重定向自Oversubscription）
Overselling or overbooking is sale of a volatile good or service in excess of actual supply. Overselling is a common practice in the travel and lodging industry, in which it is expected that some people will cancel. In telecommunications, sometimes the term oversubscription is preferred. The practice occurs as an intentional business strategy where sellers expect that some buyers will not consume all of the resources they are entitled to, or that some buyers will cancel. The practice of overselling ensures that 100% of available supply will be used resulting in the maximum return on investment. However, if most customers do wish to purchase or use the sold commodity, it may leave some customers lacking a service they expected to receive.