Ad Valorem Duty

In the context of shipping, an ad valorem duty is a tax that is calculated as a percentage of the value of the goods being imported or exported. This type of duty is used by many countries as a way to generate revenue and to protect domestic industries from foreign competition. 

The ad valorem duty is calculated based on the declared value of the goods being shipped and is typically assessed by customs authorities when the goods enter or leave the country. The amount of the duty varies depending on the type of goods and the country of origin or destination and can range from a few percent to several dozen percent of the declared value.