Importers of HS 4421.99 (spring-type) from Mexico actually paid 13.43% on the taxed portion of the value in 2026-06 — 0.05% across everything shipped, taxed or not. Measured from official duty receipts, not the rulebook: the statutory MFN base rate on this code is 6.5¢/gross. Over the window the rate on the taxed portion moved 4.96% → 13.43%, with the largest single step -18.4pp in 2025-10. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. Collected 13.43% against an HTS base of 6.5¢/gross. Reproduce exactly: tariff_story(hs: "4421.99", origin: "Mexico") · see it at trimtabist.com/tariffs
HS 4421.99. The schedule base rate is 6.5¢/gross; importers from Mexico actually paid 13.43% on the dutiable value in 2026-06. Measured, not modelled.
Over the window the collected rate moved 4.96% (2023-07) → 13.43% (2026-06), largest single step -18.4pp in 2025-10.
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 · 48 CBP rulings cite this code · reproduce: tariff_story(hs: "4421.99", origin: "Mexico") via /connect. Not customs or legal advice.