Importers of HS 8421.23 (oil or fuel filters for internal combustion engines) from Korea, South actually paid 14.85% on the taxed portion of the value in 2026-06 — 14.21% across everything shipped, taxed or not. Measured from official duty receipts, not the rulebook: the statutory MFN base rate on this code is 2.5%. Over the window the rate on the taxed portion moved 2.5% → 14.85%, with the largest single step +16.1pp in 2025-05. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is 2.5% — importers actually paid 14.85%, so the trade-war overlay added 12.3 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "8421.23", origin: "Korea, South") · see it at trimtabist.com/tariffs
HS 8421.23. The schedule base rate is 2.5%; importers from South Korea actually paid 14.85% on the dutiable value in 2026-06 — the trade-war overlay added 12.3 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved 2.5% (2023-07) → 14.85% (2026-06), largest single step +16.1pp in 2025-05.
Korea, South's lower duty (14.21% vs 48.85%) lets it price up to 30.3% above China at the factory and still match on duty-inclusive customs cost. But on the LATEST measured prices, China actually lands cheaper — $7.74/kg vs $12.05/kg (duty in, freight out).
All goods from South Korea · the whole tariff ledger · 1 CBP ruling cite this code · reproduce: tariff_story(hs: "8421.23", origin: "South Korea") via /connect. Not customs or legal advice.