Two new HTSUS codes—9903.82.18 for steel and 9903.82.19 for aluminum—now track reduced-tariff shipments under the Section 232 USMCA automotive capacity-investment program. The codes were created following the Department of Commerce's Federal Register publication implementing Presidential Proclamation 10984, issued in late 2025.
The tariff reduction mechanism allows qualifying Canadian and Mexican producers to receive cuts of up to 50% off standard Section 232 rates, but the effective rate can never drop below 25%. This floor matters for duty calculation logic: systems must validate that any computed reduction does not breach the 25% minimum threshold, regardless of the percentage reduction granted to a specific importer of record.
Eligibility verification flows through Commerce to CBP. Under the published rule, Commerce will notify CBP directly which importers of record qualify for the reduced rates. This means entry systems cannot rely solely on HTS code selection—CBP will cross-reference importer eligibility against Commerce's approved list before applying the reduced rate. Compliance teams should expect ACE validation to flag entries using 9903.82.18 or 9903.82.19 if the importer is not on the authorized list.
Origin requirements are strict: All imported steel must be melted and poured in Canada or Mexico; all aluminum must be smelted in Canada or Mexico. Products must also satisfy USMCA rules of origin. Entries that fail these criteria do not qualify for the new codes.
The quarterly volume dimension adds another layer of complexity. Reduced rates apply only to limited quarterly volumes tied directly to the amount of new US primary production capacity each company commits to building. Rate engines that cache duty rates by HTS code alone will produce incorrect calculations—volume tracking against company-specific quarterly allocations is required.
The enforcement mechanism carries retroactive risk. If a company misses project milestones—land acquisition, construction, equipment installation, or first production dates—Commerce can suspend or revoke the tariff reduction. More critically for compliance systems, CBP may retroactively apply the full Section 232 tariff rate to past imports that received the reduced rate. This creates potential duty liability that could surface months or years after entry.
Retroactive rate application warning: Systems tracking landed cost or duty drawback must account for the possibility that entries classified under 9903.82.18 or 9903.82.19 could be reliquidated at full S232 rates if the importer's US investment project fails.
The program targets a specific supply chain: steel and aluminum flowing to US automakers and heavy-duty vehicle manufacturers. Applicants must already supply these sectors and must submit detailed project plans identifying US facility locations, expected annual capacity, equipment suppliers, construction contractors, and hiring plans. Quarterly progress reports to Commerce are mandatory.
For trade compliance engineering teams, the implementation requirements are clear: update HTS reference data to include 9903.82.18 and 9903.82.19, build validation logic that checks importer eligibility against CBP notifications, enforce the 25% rate floor in duty calculations, and implement volume tracking at the importer-quarter level. Rate caching strategies must account for the conditional nature of these codes—the rate is not static per code but dependent on importer status and remaining quarterly allocation.