Major Client Postal Codes can be assigned at the initiative of the postal operator to customers in metropolitan areas with a large number of daily shipments. It provides an easier rationalization of shipping. The own postcodes may only be used for letters. Major Client Postal Codes do not work for parcel services, which are distributed and acknowledged at the customer's delivery address. Addresses using Major Client Postal Codes are entered without a delivery address, as they do not precisely define the addressee's geographical position.