Ticket resale (also known as ticket scalping or ticket touting) is the act of reselling tickets for admission to events. Tickets are bought from licensed sellers and then sold for a price determined by the individual or company in possession of the tickets. Tickets sold through secondary sources may be sold for less or more than their face value depending on demand, which tends to vary as the event date approaches. When the supply of tickets for a given event available through authorized ticket sellers is depleted, the event is considered "sold out", generally increasing the market value for any tickets on offer through secondary sellers. Ticket resale is common in both sporting and musical events. Ticket resale is a form of arbitrage that arises when the number demanded at the sale price exceeds the number supplied (that is, when event organizers charge less than the equilibrium prices for the tickets). During the 19th century, the term scalper was applied to railroad ticket brokers who sold tickets for lower rates. Purchase and re-sale methods Ticket re-sellers use several different means to secure premium and previously sold-out ticket inventories (potentially in large quantities) for events such as concerts or sporting events. Established re-sellers may operate within networks of ticket contacts, including season ticket holders, individual ticket re-sellers, and ticket brokers. They make a business out of getting customers hard-to-find and previously sold-out tickets that are no longer available through the official box office. Ticket scalpers (or ticket touts in British English) work outside events, often showing up with unsold tickets from brokers' offices on a consignment basis or showing up without tickets and buying extra tickets from fans at or below face value on a speculative basis hoping to resell them at a profit. There are many full-time scalpers who are regulars at particular venues and may even have a pool of loyal buyers. One common concern with resale is with scam artists selling fake tickets to unsuspecting buyers. Another common practice is scalpers that sell tickets that have already been scanned at the venue gate since entry is typically allowed only when a ticket is scanned for the first time. Since the tickets were authentic, buyers do not have a way of telling if a ticket had been used or not. A concern when buying tickets on the street from a ticket scalper or via an online auction is that