Aftermarket refers to the sale of something after it is originally placed on the market for sale. For example, in securities transactions, aftermarket refers to the situation in which an investor purchases a security from another investor rather than the issuer, after its original issuance in the primary market. It is also called secondary market.
The term is also commonly used in the automotive industry to refer the market for replacement parts, accessories, and equipment for the care or enhancement of a vehicle after its sale to the consumer. Some states allow insurance companies the use of aftermarket parts without consumers consent, some states require the consumer to be notified that aftermarket parts were used on their vehicle, some states require consumer consent for the use of aftermarket parts, and in a few states the use of aftermarket parts to repair a vehicle is banned. It may also be used to refer to any additional market created by a product after the primary market.