The 100% Section 232 duty on patented pharmaceutical imports has already taken effect. It started July 31, 2026 for most covered goods, and a second cohort of seventeen companies listed in Annex III of the April 2, 2026 proclamation sees it begin September 29, 2026. Anyone whose supply chain touches an imported active pharmaceutical ingredient has about five weeks before that second date, and — more importantly — the onshoring application window that would have reduced the rate closed on June 12, 2026.
That last point reframes the whole exercise. This is no longer a tariff you can apply for relief from. It is a tariff you plan around.
What the 100% Rate Actually Covers
The proclamation applies a 100% duty to pharmaceutical articles that are subject to a valid, unexpired U.S. patent — practically, products listed in the FDA’s Orange Book or Purple Book — plus the active pharmaceutical ingredients and key starting materials for those articles. The extension to APIs and KSMs is the part that pulls contract manufacturers and ingredient suppliers into scope even when they never touch a finished dosage form.
The exclusions are meaningful and worth confirming against your own portfolio:
- Generic pharmaceuticals and biosimilars, and their associated ingredients, are expressly outside the action for now. Commerce is required to advise the President within one year of the proclamation whether circumstances warrant extending Section 232 coverage to generics and their ingredients, so this is a carve-out with a review clock attached, not a settled boundary.
- U.S.-origin products, orphan drugs, development prototypes classified under HTSUS 9817.85.01, and specialty categories including nuclear medicines, cell and gene therapies, and animal health products.
- Annex IV lists HTSUS codes carrying zero-rate coverage; Annex I lists the codes that are subject to the duty. A classification-level review against both is the only way to know where a given ingredient lands.
The Rate Is Not a Single Number
The structure is tiered by origin and by company status, which means two importers of chemically identical material can face very different duties:
| Situation | Rate |
|---|---|
| Baseline, patented article or its API/KSM | 100% |
| Japan, EU, South Korea, Switzerland, Liechtenstein | 15% |
| United Kingdom | 110% |
| Commerce-approved onshoring plan | 20% |
| MFN pricing agreement with HHS (includes the 13 Annex II companies) | 0% until January 20, 2029 |
| Annex III companies (17 named) | 100%, beginning September 29, 2026 |
The country-specific 15% tier is the single most consequential line for sourcing teams. It creates a legitimate, policy-created cost differential of 85 percentage points between an EU or Japanese API source and one outside the named jurisdictions. For a high-value ingredient, that difference dwarfs every unit-cost negotiation a procurement team is likely to win this year.
Why the June 12 Deadline Still Matters
The onshoring pathway — a Commerce-approved plan reducing the duty to 20%, and to zero when paired with an MFN pricing agreement with the Department of Health and Human Services — required an application submitted by June 12, 2026. Applications ran through the Bureau of Industry and Security and had to include corporate and ownership detail, planned U.S. investments across 2025 through 2029, product-specific onshoring commitments, domestic and global sales percentages, production milestones, and a product annex carrying HTSUS codes, brand names, active ingredients, country of origin, and importer information.
If your customer or brand partner filed, their approved status governs the rate on material you supply into that program, and you need to know which of their products the approval covers. BIS review carries no statutory time limit, so an application filed in June may still be pending. For a contract manufacturer, “our customer applied” is not the same as “our shipments are covered,” and the distinction is worth pinning down in writing.
If nobody in the chain filed, the 20% and 0% tiers are simply unavailable, and the planning question becomes origin and classification rather than agreements.
Mechanics That Change Landed Cost
Two operational details deserve attention before the September 29 date.
Foreign trade zones require privileged foreign status. Covered products admitted to an FTZ must be admitted as privileged foreign status under 19 CFR § 146.41 unless they qualify for domestic status. Ingredient inventory sitting in a zone without that election does not avoid the duty; it acquires it at entry for consumption. For companies that hold API inventory in FTZs as a working-capital tool, this is a discrete item to verify rather than assume.
Drawback is available. Duties imposed under this proclamation are eligible for drawback. For a contract manufacturer that imports API, produces finished dosage form, and exports a share of output, drawback is the difference between a 100% duty being a cost and being a financing event. If your organization does not currently run a drawback program, the arithmetic on setting one up changes materially at these rates.
The Five-Week Checklist
For anyone supplying into or importing on behalf of an Annex III company, or anyone who has not yet mapped exposure:
- Match every imported ingredient against Annex I and Annex IV at the HTSUS level, and separately confirm whether the finished article it feeds is Orange Book or Purple Book listed. The patent status of the downstream product, not the chemistry of the ingredient, drives coverage.
- Confirm your customers’ annex status in writing. Annex II (MFN agreement, 0%), Annex III (delayed to September 29), or neither — this determines the rate on your shipments and is not something to infer from a press release.
- Check origin against the 15% tier. Where a qualified alternate source exists in the EU, Japan, South Korea, Switzerland, or Liechtenstein, the duty differential may justify a qualification program that would never have cleared a hurdle rate on unit cost alone. Qualification timelines for an API source are long; starting the assessment now is the actionable part.
- Review FTZ status elections on existing covered inventory.
- Model drawback on the export share of production.
- Read the generics review clock. If your business is built on generic and biosimilar ingredients, you are outside the action today and inside a Commerce review that reports within a year of April 2, 2026. Build the exposure map now, while it is a planning exercise rather than a fire drill.
The pattern across this year’s trade actions is consistent: the rate gets the headline and the annexes, effective dates, and status elections determine what anyone actually pays. September 29 is a date on a calendar. The classification work that tells you whether it matters to you is the part that has to happen first.
