For goods being imported over the value of $2500 a formal entry is required and a bond must be attached by law to that import. Also, if it is an ocean shipment then an ISF (Importer Security Filing) is required and for formal shipments a bond is required to be attached to that ISF. The fees for single transaction bond are determined by the value of the shipments and whether an OGA (outside government agency) is involved. A single ISF bond charge is based on a $10,000 bond. In general if you are importing more than once a year via ocean freight or twice a year in air freight the cost of an annual continuous bond is lower than single transaction per shipment bonds.