The basis for the granting of a quantity rebate may be the quantity of a particular product purchased from a particular seller either at one time or over a period of time (simple quantity rebate). It may also be the aggregated quantity of several products purchased from a single seller or several sellers, or of a single product purchased from several sellers. Where quantity rebates depend upon the aggregated quantity purchased by the buyer from a group of sellers, they are usually called aggregated rebates or aggregated quantity rebates. However, this term is also used to denote rebates that depend on the quantity of several products bought from the same seller. Aggregated rebate systems based on purchases made from several sellers may be adopted by a seller with or without there being a specific agreement among the several sellers. Where there is an agreement, it is usually referred to as an aggregated rebate cartel.
Inasmuch as a rebate cartel involves an agreement that effects the pricing of a product, it can be considered as a type of price cartel. These formal rebate systems must be differentiated from the informal [ad hoc] preferential treatment frequently given by individual sellers to established customers, in such forms as payment terms, delivery dates, etc.
In the period 1957 to 1968, aggregated rebate cartel arrangements were adjudicated as violating French law by the French Technical Commission for Cartels and Dominant Positions. Other known cases have related to trade within the European Free Trade Association (EFTA) and the European Economic Community (EEC). Deferred rebate and dual rebate systems of loyalty rebates are applied by a number of international shipping conferences.