U.S. imports of Styrene-Acrylonitrile (SAN) Copolymers in Primary Forms (HS 390320) totaled $9.0M in August 2026, imported from 15 countries.
Importers of Styrene-Acrylonitrile (SAN) Copolymers in Primary Forms paid $932K in duties in August 2026, an average duty rate of 10.79% — duty actually collected as a share of the imports that cleared customs, not the published tariff schedule. Styrene-Acrylonitrile (SAN) Copolymers in Primary Forms imports of $9.0M in August 2026 ran 33% above the year-to-date monthly average of $6.7M.
Last updated: August 2026 dataSAN copolymers combine the rigidity of polystyrene with the chemical resistance of acrylonitrile, making them a preferred engineering resin for transparent housewares, appliance components, and automotive trim. Classified under a single US tariff line (3903200000), the material enters in primary forms such as pellets or granules. South Korea is the dominant supplier to the US market, with Mexico and Germany also contributing meaningfully to import volumes. Importers sourcing from South Korea benefit from KORUS FTA treatment, while shipments from other origins should be evaluated for applicable duty exposure.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
172 import shipments a month
SAN is a copolymer of styrene and acrylonitrile and is classified under heading 3903.20, distinct from homopolymers of styrene (3903.11/3903.19). The acrylonitrile content gives SAN improved chemical resistance and clarity, which is the defining characteristic that separates it from GPPS or HIPS at the tariff heading level.
To claim preferential treatment under KORUS, importers must have a valid certification of origin (or importer's knowledge) demonstrating that the goods meet the applicable rules of origin, typically a tariff-shift or regional-value-content test. The certification should be retained for at least five years and be available for CBP review upon request.
ImportsExports
Imports
$9.0MYoY · free account
Exports
$4.5MYoY · free account
12-mo low · imports
Low · free accountOver the twelve months to August 2026, the U.S. imported $76.3M of Styrene-Acrylonitrile (SAN) Copolymers in Primary Forms and exported $50.3M.
Through August 2026. Source: U.S. Census Bureau.
Subheading 4 of 5 in heading 3903
Subheading 390320 · $9.0M of $100.5M
HS10 import codes under this HS6 parent, each with its own page. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Imports for consumption | Average duty rate | Dutiable Share | Duty Collected |
|---|---|---|---|---|---|
| 3903200000 | Styrene-Acrylonitrile (San) Copolymers | $8.6M | 10.79% | 85.31% | $932K |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 3903200000 | Styrene-Acrylonitrile (San) Copolymers | $4.5M |
Import lines come from the U.S. Harmonized Tariff Schedule and export lines from Schedule B. The two are numbered by different agencies, so the same 10-digit code can appear in both tables describing a different product.
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Imports · August 2026
origin
South Korea and Mexico together supply 77% of it. Japan pays 12.9% duty; Mexico 0.0%.
customs district
destination
entry
rate provision · imports
14.1% enters free of duty; duty collected equals 10.79% of imports for consumption.