Importers of HS 3907.40 (polycarbonates) from Canada actually paid 12.85% on the taxed portion of the value in 2026-06 — 0.01% across everything shipped, taxed or not. Measured from official duty receipts, not the rulebook: the statutory MFN base rate on this code is 5.8%. Over the window the rate on the taxed portion moved 5.8% → 12.85%, with the largest single step +30.5pp in 2025-09. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is 5.8% — importers actually paid 12.85%, so the trade-war overlay added 7 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "3907.40", origin: "Canada") · see it at trimtabist.com/tariffs
HS 3907.40. The schedule base rate is 5.8%; importers from Canada actually paid 12.85% on the dutiable value in 2026-06 — the trade-war overlay added 7 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved 5.8% (2023-07) → 12.85% (2026-06), largest single step +30.5pp in 2025-09.
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 · reproduce: tariff_story(hs: "3907.40", origin: "Canada") via /connect. Not customs or legal advice.