Importers of HS 3906.90 (plastics) from Korea, South actually paid 9.86% on the taxed portion of the value in 2026-06 — 4.72% across everything shipped, taxed or not. Measured from official duty receipts, not the rulebook: the statutory MFN base rate on this code is 6.3%. Over the window the rate on the taxed portion moved 6.15% → 9.86%, with the largest single step +4.4pp in 2025-09. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is 6.3% — importers actually paid 9.86%, so the trade-war overlay added 3.6 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "3906.90", origin: "Korea, South") · see it at trimtabist.com/tariffs
HS 3906.90. The schedule base rate is 6.3%; importers from South Korea actually paid 9.86% on the dutiable value in 2026-06 — the trade-war overlay added 3.6 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved 6.15% (2023-07) → 9.86% (2026-06), largest single step +4.4pp in 2025-09.
Korea, South's lower duty (4.72% vs 28.37%) lets it price up to 22.6% above China at the factory and still match on duty-inclusive customs cost. But on the LATEST measured prices, Korea, South actually lands cheaper — $2.18/kg vs $2.46/kg (duty in, freight out).
All goods from South Korea · the whole tariff ledger · reproduce: tariff_story(hs: "3906.90", origin: "South Korea") via /connect. Not customs or legal advice.