Operational Excellence (OPEX) Insight – Thursday - April 16, 2026: America Rewrites the Rules: Steel, Aluminum, Copper Tariffs Now Applied to Full Invoice Value.
Góc Nhìn Vận Hành Xuất Sắc – Thứ Năm, Ngày 16/04/2026: Mỹ Thay Đổi Luật Chơi: Thuế Thép, Nhôm, Đồng Giờ Tính Trên Toàn Bộ Hóa Đơn.
Welcome To Operational Excellence (OPEX) Insight Article For The Paid Subscriber-Only Edition.
This is the bilingual post in English and Vietnamese. Vietnamese is below.
Đây là bài viết song ngữ Anh-Việt. Tiếng Việt ở bên dưới.
English
PART 1 – OFFICIAL INFORMATION
On April 2, 2026, the President of the United States signed a sweeping Proclamation comprehensively revising the tariff regime under Section 232 of the Trade Expansion Act of 1962, applying to three strategic metal groups: steel, aluminum, and copper, along with all derivative products containing these metals. The proclamation took effect at 12:01 a.m. EDT on April 6, 2026, applying to all goods entered for consumption or withdrawn from warehouse for consumption from that moment onward — regardless of whether they had been ordered or were already in transit before the announcement date. This is not a minor adjustment or a technical addendum — this is the most comprehensive restructuring of the US metals tariff system since Section 232 was first applied to steel and aluminum in 2018, and this change carries profound operational consequences for every manufacturing enterprise globally that uses steel, aluminum, or copper in its supply chain.
The single most important and transformative change lies in the tariff base calculation. Prior to April 6, 2026, under the system in effect since June 2025, Section 232 tariffs on derivative products were calculated based on the actual metal content value within the imported product — meaning if a finished product valued at $100 contained only $30 worth of steel, the tariff applied only to that $30. From April 6, 2026, the rule changes entirely: Section 232 tariffs are now applied to the full customs value of the finished product, no longer separating the base metal value from the fabrication value. That same $100 product now has tariffs applied to the entire $100. This represents a shift in tariff philosophy: from “taxing metals” to “taxing products containing metals” — and the consequence is that the effective tariff rate surges dramatically for all derivative products, especially those with high fabrication value but moderate metal content such as automotive components, electrical equipment, prefabricated construction materials, stainless steel housewares, and industrial machinery.
The proclamation establishes three principal tariff tiers under a new tiered structure. The first tier: 50% ad valorem (calculated on full customs value) applies to steel, aluminum, and copper base articles and derivative products listed in Annex I-A of the proclamation — this is the highest and most comprehensive rate, covering the majority of basic metal products imported into the United States. The second tier: 25% ad valorem on full customs value, applying to derivative products where foreign metal content exceeds 15% by weight — this rate targets “semi finished” or finished products containing significant but not predominant metal content. The third tier: 15% combined rate (including MFN/Column 1 duty plus Section 232 duty) applied to full value for certain heavy industrial equipment and electrical grid equipment listed in Annex III, effective temporarily through December 31, 2027. Notably, the proclamation also stipulates that products with metal content below 15% by weight are exempt from Section 232 tariffs — establishing a new threshold that clearly separates “significant metal content” products from “negligible metal content” products.
The proclamation also carries two special provisions regarding origin. First, goods containing Russian origin aluminum continue to face a punitive 200% tariff rate — the highest in the entire Section 232 schedule, reflecting the maintained policy of economic isolation of Russia. Second, the United Kingdom receives preferential rates with the condition that aluminum must be smelted or most recently cast in the UK and steel must be melted and poured in the UK — meaning the origin rule is based not on where final fabrication occurs but on where primary metal processing takes place, a highly stringent standard.
And finally, the provision with the longest term impact is the authority granted to the Department of Commerce and the US Trade Representative (USTR) to add new derivative articles to the tariff list on a rolling basis if import trends threaten to undermine Section 232 objectives. This means the tariff coverage list is not fixed but can expand at any time — creating a state of permanent uncertainty for every enterprise exporting metal containing products to the United States, including steel, aluminum, copper, and derivative product manufacturers in Vietnam. For Vietnamese businesses in construction steel, aluminum profiles, mechanical components, electrical equipment, and metal housewares — sectors with significant export share to the US — this proclamation mandates immediate review of: tariff exposure, landed cost calculation, pricing strategy, and sourcing decisions, because the global manufacturing cost map — particularly for every product containing steel, aluminum, or copper — has just been completely redrawn overnight.
