Importers of HS 3920.10 (of polymers of ethylene) from Canada actually paid 12.78% 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 4.2%. Over the window the rate on the taxed portion moved 4.2% → 12.78%, with the largest single step -23.1pp in 2026-03. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is 4.2% — importers actually paid 12.78%, so the trade-war overlay added 8.6 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "3920.10", origin: "Canada") · see it at trimtabist.com/tariffs
HS 3920.10. The schedule base rate is 4.2%; importers from Canada actually paid 12.78% on the dutiable value in 2026-06 — the trade-war overlay added 8.6 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved 4.2% (2023-07) → 12.78% (2026-06), largest single step -23.1pp in 2026-03.
7 Chapter-99 measures name Canada; 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 Canada · the whole tariff ledger · 3 CBP rulings cite this code · reproduce: tariff_story(hs: "3920.10", origin: "Canada") via /connect. Not customs or legal advice.