Importers of HS 8421.23 (oil or fuel filters for internal combustion engines) from Mexico actually paid 20.19% on the taxed portion of the value in 2026-06 — 1.03% 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% → 20.19%, with the largest single step +23.2pp in 2025-03. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is 2.5% — importers actually paid 20.19%, so the trade-war overlay added 17.7 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "8421.23", origin: "Mexico") · see it at trimtabist.com/tariffs
HS 8421.23. The schedule base rate is 2.5%; importers from Mexico actually paid 20.19% on the dutiable value in 2026-06 — the trade-war overlay added 17.7 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved 2.5% (2023-07) → 20.19% (2026-06), largest single step +23.2pp in 2025-03.
Mexico's lower duty (1.03% vs 48.85%) lets it price up to 47.3% 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 $57.9/kg (duty in, freight out).
5 Chapter-99 measures name Mexico; scope mapping is partial (several annexes are PDFs) — absence never means exemption. They do not sum, and some are product-specific — the collected rate above is the composed truth.
All goods from Mexico · the whole tariff ledger · 1 CBP ruling cite this code · reproduce: tariff_story(hs: "8421.23", origin: "Mexico") via /connect. Not customs or legal advice.