The US Department of Commerce has issued preliminary anti-dumping duties of up to 65.72% on Korean monomers and oligomers used as raw materials and intermediates in chemical production, signaling potential cost increases for global buyers sourcing these inputs from South Korea. The decision, announced on May 31 local time, affects two Korean companies that responded to the investigation, while a third non-responsive firm faces a 188% duty rate. This development underscores heightened trade scrutiny on chemical supply chains and may prompt importers to reassess sourcing strategies.
Preliminary duty rates
For the two Korean companies that cooperated with the investigation, the Commerce Department preliminarily calculated dumping margins of 10.94% (Company A) and 65.72% (Company B). These rates are significantly lower than the 137–188% margins originally claimed by the US industry petitioners, but still represent a substantial cost burden for exporters.
Impact on non-cooperating firms
A third Korean company, which did not respond to the Commerce Department's pre-inquiry questionnaire, received the highest possible margin of 188%. This reflects the application of 'adverse facts available' (AFA), a mechanism that allows the US authority to use the most unfavorable information when a target firm fails to cooperate fully.
What buyers should watch
Importers of Korean monomers and oligomers should monitor the final determination expected in May 2025, when the Commerce Department will issue its definitive ruling after on-site verification and further review. The preliminary duties serve as the basis for provisional anti-dumping tariffs applied at the customs clearance stage, meaning affected shipments may already face higher costs.
Korea's response and industry context
South Korea's Ministry of Trade, Industry and Energy stated it has been communicating with industry associations and companies since April 2024, warning about the potential for AFA application and guiding responses. A ministry official said they will continue to coordinate with industry to ensure Korean firms are not unfairly treated in the final ruling.
China sourcing context
For global chemical buyers, this case highlights the increasing trade friction affecting Asian chemical raw material suppliers. While Korean producers face new duties, Chinese manufacturers of similar monomers and oligomers may become alternative sourcing options, though they too could face separate US trade actions. Buyers should evaluate supply diversification and monitor ongoing anti-dumping cases across the region.
Source: Read the original report | Published: January 02, 2026