US Commerce finds Korean monomers, oligomers dumped; duties likely
The U.S. Department of Commerce has issued a final affirmative determination that certain monomers and oligomers from South Korea are being sold in the United States at less than fair value (LTFV), covering the period January 1–December 31, 2024. The agency also made a final affirmative determination of critical circumstances, meaning dumped imports are likely to cause material injury to the domestic industry. This triggers countervailing duty investigations and will lead to provisional duties pending final injury determination by the International Trade Commission (ITC).
Photo: Theodore Nguyen / Pexels# US Commerce Finds Korean Monomers, Oligomers Dumped
The U.S. Department of Commerce announced on May 27, 2026, a final affirmative determination that certain monomers and oligomers from the Republic of Korea are being, or are likely to be, sold in the United States at less than fair value (LTFV). The investigation covered the period January 1, 2024, through December 31, 2024.
What Is Affected
The investigation concerns monomers and oligomers, chemical precursors used in plastics, coatings, adhesives, and other industrial applications. Commerce's final affirmative LTFV finding means the agency concluded that Korean exporters sold these products to the U.S. market at prices below their home-market or constructed value, constituting dumping under U.S. trade law.
The U.S. Department of Commerce determines that certain monomers and oligomers from the Republic of Korea are being, or are likely to be, sold in the United States at less than fair value (LTFV). (Federal Register, May 27, 2026)
Critical Circumstances
Commerce also made a final affirmative determination of critical circumstances. This finding is significant because it means the agency determined that dumped imports are likely to cause material injury to the domestic industry, and that suspension of the investigation would not be sufficient remedy. Critical-circumstances findings typically result in the imposition of provisional duties backdated, rather than awaiting the final injury determination from the International Trade Commission (ITC).
Next Steps
The affirmative dumping determination triggers the next phase of the antidumping investigation. The ITC will now conduct its own investigation to determine whether dumped imports from Korea have caused or threaten to cause material injury to the U.S. industry. Pending the ITC's final determination, provisional antidumping duties will be assessed on entries of these monomers and oligomers.
Importers of Korean monomers and oligomers should expect duty assessments and cash-deposit requirements on shipments. The final antidumping duty rates will be determined based on Commerce's individual margins for each exporter and producer.
What this means for shippers
If you source monomers or oligomers from South Korea, you now face provisional antidumping duties on all entries. Verify the HS classification of your specific products immediately—this determination covers a defined product scope. Budget for increased landed costs, update your supplier contracts to clarify who bears the duty burden, and consider whether alternative suppliers outside Korea are cost-competitive. Monitor the ITC's injury determination (expected within 120 days) to confirm final duty rates. Failure to account for these duties in pricing and forecasting will erode margins significantly.
