The independent observatory for US trade — ship movements,
customs records and policy events, measured and tested.
What United Kingdom actually pays on prepared culture media for development or maintenance of mic
Importers of HS 3821.00 (prepared culture media for development or maintenance of mic) from United Kingdom actually paid 14.91% on the taxed portion of the value in 2026-06 — 14.91% across everything shipped, taxed or not. Measured from official duty receipts, not the rulebook: the statutory MFN base rate on this code is 5%. Over the window the rate on the taxed portion moved 5% → 14.91%, with the largest single step +7.2pp in 2025-04. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is 5% — importers actually paid 14.91%, so the trade-war overlay added 9.9 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "3821.00", origin: "United Kingdom") · see it at trimtabist.com/tariffs
HS 3821.00. The schedule base rate is
5%; importers from United Kingdom actually paid 14.91% on the
dutiable value in 2026-06 — the trade-war overlay added 9.9 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved 5% (2023-07) → 14.91% (2026-06), largest single step +7.2pp in 2025-04.
The trade-war measures that name United Kingdom or this sector
15 Chapter-99 measures name United Kingdom; 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.
Procedures for Submissions by Certain Steel and Aluminum Producers Committing to New U.S. Steel or Aluminum… measure 9903.82.04 · Federal Register citation+25%
Notice of Determination and Action Pursuant to Section 301: Enforcement of U.S. WTO Rights in Large Civil Airc measure 9903.89.10 · Federal Register citation+25%
Notice of Determination and Action Pursuant to Section 301: Enforcement of U.S. WTO Rights in Large Civil Airc measure 9903.89.13 · Federal Register citation+25%
Notice of Determination and Action Pursuant to Section 301: Enforcement of U.S. WTO Rights in Large Civil Airc measure 9903.89.16 · Federal Register citation+25%
Notice of Determination and Action Pursuant to Section 301: Enforcement of U.S. WTO Rights in Large Civil Airc measure 9903.89.19 · Federal Register citation+25%
Notice of Determination and Action Pursuant to Section 301: Enforcement of U.S. WTO Rights in Large Civil Airc measure 9903.89.22 · Federal Register citation+25%
Notice of Determination and Action Pursuant to Section 301: Enforcement of U.S. WTO Rights in Large Civil Airc measure 9903.89.25 · Federal Register citation+25%
Notice of Determination and Action Pursuant to Section 301: Enforcement of U.S. WTO Rights in Large Civil Airc measure 9903.89.28 · Federal Register citation+25%
In print: “What United Kingdom actually pays on prepared culture media for development or maintenance of mic (HS 3821.00)” —
Trimtab US Trade Ledger (TT-010 Duty receipts), US Census imports-for-consumption records — trimtabist.com/tariff/382100/united-kingdom