Importers of HS 8531.10 (burglar or fire alarms and similar apparatus) from Mexico actually paid 11.28% on the taxed portion of the value in 2026-06 — 0.53% across everything shipped, taxed or not. Measured from official duty receipts, not the rulebook: the statutory MFN base rate on this code is 1.3%. Over the window the rate on the taxed portion moved 1.3% → 11.28%, with the largest single step +22.7pp in 2025-03. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is 1.3% — importers actually paid 11.28%, so the trade-war overlay added 10 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "8531.10", origin: "Mexico") · see it at trimtabist.com/tariffs
HS 8531.10. The schedule base rate is 1.3%; importers from Mexico actually paid 11.28% on the dutiable value in 2026-06 — the trade-war overlay added 10 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved 1.3% (2023-07) → 11.28% (2026-06), largest single step +22.7pp in 2025-03.
Mexico's lower duty (0.53% vs 35.57%) lets it price up to 34.9% above China at the factory and still match on duty-inclusive customs cost. But on the LATEST measured prices, China actually lands cheaper — $14.05/kg vs $35.57/kg (duty in, freight out).
7 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 · reproduce: tariff_story(hs: "8531.10", origin: "Mexico") via /connect. Not customs or legal advice.