Antidumping Duty (AD)

An antidumping duty is an extra import tax the US imposes when a foreign producer sells goods into the American market below fair value (either below its home-market price or below its cost of production), injuring a US industry. The Commerce Department calculates a 'dumping margin' and sets the duty to offset it, so rates are product- and company-specific and can run anywhere from a few percent to over 300%. Example: a US shrimp importer sourcing from a supplier under an active AD order might owe 25% antidumping duty on top of the normal MFN rate, Section 301, and any other layers. It matters because AD duties are among the most punishing charges an importer can face, they stack on top of every other tariff, and unlike ordinary duties they generally cannot be recovered through duty drawback.