Supporting+documents

**Definition/Scope**
Supporting documents are those trade, transport and official documents that either support specific statements made in the goods declaration, such as the commercial invoice (e.g. for the invoice amount, seller and buyer), the transport document (e.g. for the consignor, consignee, means and mode of transport) or the certificate of origin, or that have to be submitted as proof of specific import/export conditions being met (e.g. import/export permits, health certificates and certificates of conformity with technical standards).

**Problem statement**
The number of documents to be submitted in support of a goods declaration is often excessive, thus adding significant cost to the trade transaction. Many such documents do not follow the UN Layout key, which hinders rationalization of these documents. They are also issued on paper, which requires manual handling as well as sometimes translation into the language of the importing country. Finally, many countries require consular verification of such documents against payment, in particular of the commercial invoice, because the authenticity of these commercial documents is questioned. Consular verification, however, adds additional cost and delays to the trade transaction.

**Implementation guidance**
As stipulated by Standard 3.16 and Transitional Standard 3.18 of the Revised Kyoto Convention (RKC), Customs shall limit the documents required to that necessary for Customs control and compliance purposes, and shall allow the lodgement of these documents by electronic means. Standard 3.19 of the RKC requires that translations shall not be required, unless necessary for processing the goods declaration.

Rather than converting paper documents into electronic files, e.g. by scanning, the current trend is the dematerialization of supporting documents. This means either eliminating a document that has proven to be no longer required, or replacing it with an electronic equivalent at source. For most trade and transport documents, there are already electronic equivalents, either in the form of UN/EDIFACT messages or in the form of electronic XML documents. In addition to these technical capabilities, a legal base has also been established, e.g. Montreal Convention for the air waybill. For official documents, such as a health certificate issued by the importing country, the development of Single Windows will enable exchange of relevant information among the government entities concerned. For official documents issued by the country of export, such as a certificate of origin, cross-border cooperation and information exchange provide a viable option for eliminating the paper version, e.g. through secure access to the document/information on the foreign agency's website.

**Additional information (references, examples, etc.)**
The ASEAN Single Window already includes an electronic certificate of origin among ASEAN countries, and an APEC Study on the electronic certificate of origin among APEC economies estimated a reduction in trade costs of 6,79 %.