The World Trade Organization has ruled aspects of US anti-dumping measures on frozen warmwater shrimp from Vietnam break world trade laws.

The WTO said “certain of the measures…are inconsistent with the General Agreement on Tariffs and Trade (GATT) and the Anti-Dumping Agreement”. It recommended the US amend the measures but did not say it should revoke the duty order in its entirety, as Vietnam had requested.

The complaint focused on the incorrect use by the US of a calculation method – simple zeroing methodology – to determine the dumping margins and on the assignment of a single rate to all Vietnamese companies by presuming that they belonged to a single Vietnam-wide entity. Vietnam brought its concerns to the WTO in 2012.