3926.90.99 and Section 338 Canada: Rates, Scope, and Stacking

Key Points

• HTS 3926.90.99 (other plastic articles) carries a general MFN duty rate of 5.3% as of August 2026.
• Section 338 applies to Canadian-origin goods entered on or after August 19, 2026; the applicable Chapter 99 overlay code rides alongside 3926.90.99 as a separate line on the entry.
• Goods imported under qualifying free-trade agreements or preference programs may enter duty-free; confirm your preference eligibility before paying the MFN rate.
• Two civil aircraft exemption codes (9903.96.01 and 9903.96.02) and one Section 301 Brazil code (9903.05.05) are cross-referenced to this classification and carry 0% additional duty where applicable.
• Column 2 (non-MFN) imports face an 80% rate, which is a practical ceiling reserved for countries without normal trade relations.

On this page

1. What HTS 3926.90.99 covers
2. The MFN rate, preference rates, and Column 2 rate
3. Section 338 Canada overlay: scope and effective date
4. How Chapter 99 codes stack on an entry
5. Other Chapter 99 overlays cross-referenced to 3926.90.99
6. What importers should do
7. Key references

HTS 3926.90.99 is the residual "other" subheading under heading 3926 of Chapter 39 (plastics and articles thereof). It captures plastic articles that do not fall under a more specific subheading within Chapter 39. As of August 12, 2026, Canadian-origin goods classified here are subject to a 5.3% general MFN duty rate plus any applicable Section 338 Chapter 99 overlay for entries on or after August 19, 2026. The links in this article go to the primary documents: the proclamations, Federal Register notices, and official tariff schedule pages themselves. Read the source.

What HTS 3926.90.99 covers

Heading 3926 covers other articles of plastics and articles of other materials in headings 3901 through 3914. Subheading 3926.90.99 is the catch-all residual: it reaches miscellaneous plastic articles not enumerated elsewhere in the chapter. The article description in the tariff schedule is simply "Other."

Because this is a residual provision, the classification universe is broad. If a plastic article has no more-specific home in Chapter 39 or in another chapter by operation of Section or Chapter notes, 3926.90.99 is the landing spot. Confirm the correct classification with your customs broker or against the current HTSUS if there is any question whether a more specific subheading applies to your product.

You can view the live subheading on the official tariff schedule at hts.usitc.gov. For a broader overview of 2026 tariff code activity, see our 2026 tariff code overview.

The MFN rate, preference rates, and Column 2 rate

General (Column 1 / MFN) rate

The general duty rate for 3926.90.99 is 5.3% ad valorem. This rate applies to goods from countries that have normal trade relations with the United States and are not covered by a preferential program listed below.

Preference (Special) rates

Goods from the following countries or preference programs may enter free of duty under the Special rate column:

• Free: A (GSP), AU (Australia FTA), B (AGOA), BH (Bahrain FTA), C (CAFTA-DR general), CL (Chile FTA), CO (Colombia FTA), D (AGOA enhanced), E (Caribbean Basin Initiative), IL (Israel FTA), JO (Jordan FTA), KR (Korea FTA), MA (Morocco FTA), OM (Oman FTA), P (Dominican Republic-CAFTA), PA (Panama FTA), PE (Peru FTA), S (CAFTA-DR special), SG (Singapore FTA)

Confirm that your goods meet the applicable rules of origin and that the relevant program is active before claiming a preference. Canada is not among the qualifying special-rate countries for this subheading under the standard FTA column; the Canada situation is governed by Section 338 (see next section).

Column 2 rate

Goods from countries without normal trade relations are subject to a 80% ad valorem rate under Column 2. This rate applies to a very small set of trading partners; most commercial importers will not encounter it.

Section 338 Canada overlay: scope and effective date

Section 338 is the trade-action program that places an additional duty on Canadian-origin goods. HTS 3926.90.99 is on the Section 338 Canada article list. The overlay applies to entries on or after August 19, 2026. Goods of Canadian origin entered before that date are not subject to the Section 338 additional duty under this program.

The Section 338 Chapter 99 codes that cover this classification run from 9903.03.12 through 9903.03.16. The correct code within that range for your specific goods should be confirmed against the current HTSUS and with your broker, as the subrange designations within 9903.03.12-9903.03.16 may differentiate by product or rate tier. (Note: codes 9903.03.01 through 9903.03.11 belong to the Section 122 block, which is no longer operative.)

For additional context on how Section 338 is applied to other Chapter 39 plastic articles, see our related article on 3926.40.00 and Section 338 Canada.

How Chapter 99 codes stack on an entry

Chapter 99 overlay codes do not replace the underlying Chapter 1-97 classification. Instead, each applicable Chapter 99 code appears as its own separate line element on the entry alongside the 3926.90.99 line. The additional duty imposed by the Chapter 99 code is on top of the 5.3% MFN rate (or any applicable preference rate). They are cumulative unless an exemption explicitly provides otherwise.

Practical consequence: when your broker prepares the entry summary, you should see 3926.90.99 reported with its 5.3% (or preference) rate, and one or more Chapter 99 codes reported as additional lines, each with their own additional duty rate. The duty bill reflects all applicable layers. Use our duty calculator to model the stacked total landed cost.

For a deeper look at entry reporting obligations and broker oversight, see Customs Broker Oversight as an Importer Duty: What You Must Do.

Other Chapter 99 overlays cross-referenced to 3926.90.99

As of August 12, 2026, three additional Chapter 99 codes are cross-referenced to this classification. Each carries distinct conditions and effective windows.

9903.05.05 (Section 301 Brazil Exemptions)

Rate: the duty provided in the applicable subheading (i.e. the underlying rate, meaning the overlay does not add to it in this context). Effective from July 22, 2026 onward, with no announced end date. This code applies only when the entry qualifies under the Section 301 Brazil exemption framework. Confirm applicability with your broker before claiming.

9903.96.01 (Civil Aircraft Exemption)

Rate: 0% additional duty. Effective from June 30, 2025 onward, with no announced end date. This exemption applies to qualifying civil aircraft parts and components. If your plastic article qualifies as a civil aircraft part, this overlay eliminates the additional duty that would otherwise apply under covered Section programs.

9903.96.02 (Civil Aircraft Exemption)

Rate: 0% additional duty. Effective from September 16, 2025 onward, with no announced end date. A second civil aircraft exemption code covering a different tranche or category of qualifying aircraft-related goods. Confirm which code applies based on your specific goods and entry date.

These overlays are separate from the Section 338 Canada overlay. A given entry could in principle carry multiple Chapter 99 lines if the goods meet more than one overlay's conditions. Work through applicability one code at a time with your broker.

What importers should do

• Verify classification now. Because 3926.90.99 is a broad residual provision, confirm that no more-specific Chapter 39 subheading covers your goods before the August 19, 2026 Section 338 effective date. Check the current HTSUS at hts.usitc.gov and consult your broker.
• Determine Canadian-origin status. Section 338 applies only to goods of Canadian origin entered on or after August 19, 2026. Document your origin determination and ensure your broker reports the correct 9903.03.12-9903.03.16 code on qualifying entries.
• Audit stacking for every applicable Chapter 99 code. Check whether 9903.05.05, 9903.96.01, or 9903.96.02 applies to your goods. Each is a separate entry line and each has its own eligibility conditions and effective dates. A missed exemption means overpaying; an improperly claimed one creates liability. Our article on Post Entry Audit Program: Build a Monthly Self-Review outlines a practical review cadence.
• Model your landed cost before import. Stack all applicable rates: 5.3% MFN (or 0% preference if eligible), plus the Section 338 overlay rate for Canadian goods, minus any civil aircraft or Brazil exemption credits. Use the duty calculator to build a complete picture before your entry is filed.

Key references

• Harmonized Tariff Schedule of the United States (HTSUS), hts.usitc.gov: official live schedule including 3926.90.99 and all Chapter 99 overlay codes.
• Federal Register, federalregister.gov: notices and rules implementing Section 338 Canada additional duties and Section 301 Brazil exemptions.
• White House proclamations and executive orders, whitehouse.gov: executive actions establishing Section 338 and related trade programs.
• U.S. Customs and Border Protection, cbp.gov: CSMS messages and guidance on entry reporting of Chapter 99 overlay codes.
• 3926.40.00 and Section 338 Canada: Rates, Scope, and Stacking: companion article covering a related Chapter 39 plastic subheading under Section 338.
• Customs Broker Oversight as an Importer Duty: What You Must Do: guidance on importer obligations when relying on broker entry preparation.