Importers of HS 3920.10 (of polymers of ethylene) from Vietnam actually paid 13.06% on the taxed portion of the value in 2026-06 — 13.02% across everything shipped, taxed or not. Measured from official duty receipts, not the rulebook: the statutory MFN base rate on this code is 4.2%. Over the window the rate on the taxed portion moved 4.2% → 13.06%, with the largest single step -8.4pp in 2026-03. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is 4.2% — importers actually paid 13.06%, so the trade-war overlay added 8.9 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "3920.10", origin: "Vietnam") · see it at trimtabist.com/tariffs
HS 3920.10. The schedule base rate is 4.2%; importers from Vietnam actually paid 13.06% on the dutiable value in 2026-06 — the trade-war overlay added 8.9 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved 4.2% (2023-07) → 13.06% (2026-06), largest single step -8.4pp in 2026-03.
Vietnam's lower duty (13.02% vs 39.05%) lets it price up to 23% above China at the factory and still match on duty-inclusive customs cost. But on the LATEST measured prices, Vietnam actually lands cheaper — $1.62/kg vs $2.09/kg (duty in, freight out).
All goods from Vietnam · the whole tariff ledger · 3 CBP rulings cite this code · reproduce: tariff_story(hs: "3920.10", origin: "Vietnam") via /connect. Not customs or legal advice.