Washington -- The U.S. Department of Commerce has made a preliminary determination that imports of frozen catfish from Vietnam were dumped on the U.S. market.

In a January 27 fact sheet the department said it calculated the dumping margins range from 37.94 to 61.88 percent.

Imposition of antidumping duties requires final affirmative determinations both from the Commerce Department that dumping occurred and from the U.S. International Trade Commission (USITC) that the imports injured or threatened U.S. industry.

The Commerce final determination is expected by June. In the meantime the U.S. Customs Service will collect a cash deposit or bond equal to the dumping margin on any such imports; it would return the money in the event of a negative determination.

The department calculated the dumping margins as follows for four mandatory Vietnamese respondents to its investigation: Agifish, 61.88 percent; Cataco, 41.06 percent; Nam Viet, 53.96 percent; Vinh Hoan, 37.94 percent.

The department assigned a margin of 49.16 percent for six other companies that voluntarily responded to the investigation questionnaire. All other such imports from Vietnam would be subject to a Vietnam-wide rate of 63.88 percent.

Commerce has made a preliminary ruling that "critical circumstances" pertains to imports from Nam Viet and imports subject to the Vietnam-wide rate. If Commerce and USITC make affirmative final rulings on critical circumstances, then antidumping duties would be imposed on those imports retroactively 90 days to October.

Under U.S. antidumping law, critical circumstances may be found when there is a massive surge in imports following -- or immediately preceding -- initiation of the antidumping investigation. The purpose of the provision is to prohibit the importation of large quantities of merchandise before a determination can be made that the merchandise is being dumped.

The Commerce Department ruled that, for the purpose of U.S. antidumping laws, Vietnam was still a non-market economy. That means the Commerce investigation looks for prices in a surrogate market, not Vietnam's home prices, when calculating dumping margins.

In January-November 2002 U.S. imports of frozen catfish from Vietnam amounted to $55 million.

Dumping is the import of goods at a price below the home-market or a third-country price or below the cost of production. A dumping margin represents by how much the fair-value price exceeds the dumped price.