Executive summary

On 1 June 2026, the United States (US) President issued a proclamation titled "Further Adjusting the Tariff Regimes for Imports of Aluminum, Steel, And Copper into the United States," amending the tariff regimes imposed under Section 232 of the Trade Expansion Act of 1962 on imports of aluminum, steel and copper and their derivative products.

The action modifies tariff rates and product coverage established under prior proclamations, including the most recent framework introduced under Proclamation 11021, which imposed a tiered duty structure of 50%, 25% and 15% depending on product characteristics.

For more on the framework introduced under Proclamation 11021, see EY Global Tax Alert, US presidential proclamation modifies Section 232 tariffs on steel, aluminum, copper and their derivative products, dated3 April 2026.

Key changes include expanding the scope of products eligible for the reduced 15% duty rate, revising tariff treatment for certain imported products, adding new derivative products to coverage and lowering the US-origin content threshold required for preferential treatment.

These changes are intended to balance national security objectives with economic considerations affecting downstream industries and supply chains.

Background

Since 2018, the United States has imposed tariffs on imports of steel and aluminum under Section 232, later extended to copper products, based on findings that these imports threaten to impair national security.

In April 2026, Proclamation 11021 significantly revised the tariff structure by:

• Imposing a 50% duty on primary metal products
• Applying a 25% duty on most derivative products
• Introducing a temporary 15% duty for a subset of industrial machinery and equipment

The 1 June 2026 proclamation further refines this framework based on recommendations from the US Secretary of Commerce (the Secretary), particularly to address impacts on domestic industries that rely on metal-based equipment and machinery.

Scope of modifications

The proclamation expands the scope of derivative products subject to the temporarily reduced 15% ad valorem duty to include:

• Agricultural equipment
• Certain residential heating, ventilation and air conditioning (HVAC) systems and components

The proclamation also introduces temporary tariff modifications for mobile industrial equipment and machinery, recognizing their role in industrial operations and manufacturing.

Expanded tariff coverage

The proclamation adds new products to the derivative tariff regime, including aluminum lithographic plates and steel racks, to prevent circumvention.

Revised origin threshold

The proclamation lowers the threshold for products to qualify as made "entirely" from US-origin metal inputs from 95% to 85% by weight.

This change applies to aluminum, steel and copper content and is intended to encourage greater use of US-produced metals in downstream products.

Annex I-C tariff framework and country-specific treatment

General tariff structure (through 31 December 2027)

Effective for covered goods entered on or after 8 June 2026, the revised framework provides for a 25% tariff on listed aluminum and steel articles, unless a lower rate applies.

Country-specific treatment

For articles originating from Argentina, Ecuador, El Salvador, Guatemala, Japan, the Republic of Korea, Liechtenstein, Switzerland, Taiwan, the United Kingdom, or a European Union (EU) member state:

• Tariff rates are adjusted based on the product's Column 1 Harmonized Tariff Schedule of the United States (HTSUS) rate, with a minimum effective duty of 15%

For products meeting the 85% US-origin (based on country of melt and pour for steel or smelt and cast for aluminum) metal requirements:

• Reduced rate of 10%

US-Mexico-Canada Agreement (USMCA) treatment

• For USMCA-qualifying products from Canada and Mexico, the 25% duty applies only to non-US content, defined as total value less the value of US origin parts.
• The total effective duty shall not be less than 15% ad valorem, as set out in Annex IV.
• The Secretary shall issue US Customs and Border Protection (CBP) guidance on determining "US content" for purposes of this calculation.

Post-2027 framework

• Beginning on 1 January 2028, tariff rates will revert to those established under Proclamation 11021, unless further modified.

What this means for businesses

The proclamation introduces several operational and compliance considerations:

• Changes to applicable tariff rates and product coverage may increase duties for certain imports while reducing duties for others.
• Newly covered products (e.g., steel racks) and expanded derivative categories require careful classification review.
• The revised 85% threshold and USMCA-specific rules require updated methodologies for determining US-origin content.
• Companies may need to adjust sourcing strategies to qualify for lower tariff rates or mitigate overall tariff exposure.
• Increased scrutiny on origin declarations and content calculations may elevate compliance and enforcement risk.

Key dates

• 1 June 2026: Proclamation issued
• 8 June 2026: Effective date
• 31 December 2027: End of temporary measures
• 1 January 2028: Reversion to prior tariff structure

Actions to consider

Businesses affected by these changes should consider:

• Evaluating product classifications and identifying newly covered derivative products
• Assessing eligibility for reduced tariff rates, including the 15% category and US-origin thresholds
• Updating origin and content calculation methodologies to reflect the 85% threshold
• Modeling financial impact of revised tariff rates and exploring customs planning strategies
• Reviewing USMCA qualification processes and supporting documentation for determining and documenting US content
• Monitoring forthcoming guidance from the Department of Commerce and CBP, including staying current with the USMCA review process