The return of a portion of the freight charges by a carrier or a conference shipper in exchange for the shipper giving all or most of his shipments to the carrier or conference over a specified period of time (usually six months). Payment of the rate is deferred for a further similar period, during which the shipper must continue to give all or most of his shipments to the rebating carrier or conference. The shipper thus earns a further rebate that will not, however, be paid without an additional period of exclusive or almost exclusive patronage with the carrier of conference. In this way, the shipper becomes tied to the rebating carrier or conference. Although the deferred rebate system is illegal in U.S. foreign commerce, it generally is accepted in the ocean trade between other countries.