Section 338 list for Canadian goods is modified effective Sept. 15, 2026, changing which HTS lines incur 50% additional duties and who may claim 9903.03.15.

CBP’s CSMS #69851916 implements Presidential Proclamations modifying Section 338 additional duties on certain Canadian-origin goods. Section 338 duties are retaliatory measures to offset Canadian discrimination against U.S. commerce in alcoholic beverages, dairy, and motor vehicles. Proclamation 11056 removed a prior suspension and imposed additional duties of 50% ad valorem on certain Canadian products effective August 22, 2026. The September 8, 2026 proclamations (Proc. 11064 and 11065) further adjust the scope of covered products.

Effective for goods entered for consumption, or withdrawn from warehouse for consumption, on or after 12:01 a.m. Eastern time on September 15, 2026, the Section 338 coverage is modified as follows:

1) HTSUS 9903.03.12, 9903.03.13, and 9903.03.14 remain the operative Chapter 99 provisions for Section 338 duties on Canadian-origin goods. Each carries a 50% additional ad valorem rate of duty on top of the normal duty and any ADD/CVD:

• 9903.03.12: Articles the product of Canada as provided in U.S. note 51(b)(1).
• 9903.03.13: Articles the product of Canada as provided in U.S. note 51(b)(2).
• 9903.03.14: Articles the product of Canada as provided in U.S. note 51(b)(3).

The attached HTS list (Section 338 Canada Modified HTS LIST eff 091526) provides the complete set of underlying HTS classifications subject to these headings as of September 15, 2026. It includes 122 additional HTS lines newly subject to 9903.03.12 or 9903.03.14. Brokers must use this list to determine when to apply the 50% additional duty.

2) Certain HTS lines are explicitly removed from Section 338 coverage as of September 15, 2026. The following underlying HTSUS classifications, previously tied to 9903.03.12 or 9903.03.14, are no longer subject to Section 338 additional duties:

• For 9903.03.12: 2208.30.60, 2208.70.00.
• For 9903.03.14: 2501.00.00, 2523.29.00, 2940.00.60, 4803.00.40, 4818.90.00, 7801.10.00, 8537.10.91, 9507.10.00.

For Canadian-origin goods classified in these HTS lines, brokers should stop declaring the associated Section 338 Chapter 99 subheading and should not assess the 50% additional duty for entries on or after September 15, 2026. Prior entries (from August 22, 2026 up to September 14, 2026) remain subject to the rules in effect at that time.

3) HTSUS 9903.03.15 and 9903.03.16 are clarified:

• 9903.03.15 covers articles of aluminum, steel, copper, derivative aluminum or steel articles; passenger vehicles and light trucks and their parts; medium- and heavy-duty vehicles and their parts; wood products; semiconductor articles; and patented pharmaceutical articles, as described in U.S. note 51(c). The additional duty rate under 9903.03.15 is 0% ad valorem.
• 9903.03.16 covers civil aircraft and related engines, parts, components, subassemblies, and ground flight simulators of Canadian origin, as described in U.S. note 51(d). The additional duty rate under 9903.03.16 is also 0% ad valorem.

The key change is eligibility for 9903.03.15: as of September 15, 2026, only goods that are subject to 9903.03.13 may claim 9903.03.15. This means that the 0% additional duty provision is now limited to a subset of Canadian goods already within the 9903.03.13 scope. Brokers must ensure that 9903.03.15 is not claimed for goods outside 9903.03.13 coverage.

4) Interaction with other duties and trade remedies: Products provided for in headings 9903.03.12 through 9903.03.16 remain subject to any applicable antidumping and countervailing duties, as well as other duties, taxes, fees, and exactions. The 50% additional ad valorem duty under 9903.03.12–9903.03.14 is applied in addition to base MFN/FTA rates and ADD/CVD.

5) Chapter 98 treatment: The additional duty imposed by 9903.03.12–9903.03.14 does not apply to goods properly entered under most Chapter 98 provisions, provided CBP agrees that such entry is appropriate. However, there are important exceptions:

• Goods entered under subchapter XXIII of Chapter 98, and under subheadings 9802.00.40, 9802.00.50, 9802.00.60, and heading 9802.00.80, remain subject to the additional duty.
• For 9802.00.40, 9802.00.50, and 9802.00.60, the 50% additional duty applies to the value of repairs, alterations, or processing performed abroad.
• For 9802.00.80, the 50% additional duty applies to the value of the article assembled abroad, less the cost or value of U.S. products incorporated, as described in that heading.

Brokers using Chapter 98 for Canadian-origin goods must therefore determine whether the Section 338 additional duty is waived or must be calculated on the specified value components.

6) Foreign Trade Zones (FTZ): Any product subject to Section 338 duties that is admitted into a U.S. FTZ, and is not eligible for domestic status, must be admitted in privileged foreign status. Upon entry for consumption from the FTZ, the merchandise will be subject to the applicable ad valorem rate of duty, including the 50% additional duty where 9903.03.12–9903.03.14 apply. FTZ operators and brokers must ensure correct status designation and duty calculation at the time of consumption entry.

7) Drawback: The additional duties imposed by 9903.03.12–9903.03.14 are eligible for drawback. Companies operating drawback programs should update their internal matrices to include Section 338 additional duties as recoverable where statutory and regulatory conditions are satisfied.

Operationally, customs brokers and trade compliance teams should: (1) load the attached modified HTS list into their classification and screening tools; (2) reconfigure their systems to apply 9903.03.12, 9903.03.13, or 9903.03.14 with a 50% additional ad valorem duty for covered Canadian-origin goods entered on or after September 15, 2026; (3) cease applying Section 338 duties to the HTS lines explicitly removed; (4) restrict use of 9903.03.15 to goods that are also subject to 9903.03.13; and (5) adjust Chapter 98, FTZ, and drawback procedures to reflect the specific Section 338 rules. For complex cases, CBP’s Trade Remedy Branch (TradeRemedy@cbp.dhs.gov) can provide further guidance.