9903.05.55 Mexico Section 301 Forced Labor: 10% Duty Explained

Key Points

• HTS 9903.05.55 imposes an additional 10 percent ad valorem duty on all products of Mexico (all chapters 1 through 97) under the Section 301 Forced Labor program, effective July 24, 2026, with no announced end date.
• The legal basis is the USTR Section 301 Forced Labor Investigation (FLIP) final action dated July 23, 2026, implemented through U.S. note 52 and CSMS message 69326983.
• Every chapter 1-97 product of Mexican origin is in scope; there is no product-specific exclusion list described in the facts available as of September 9, 2026.
• 9903.05.55 is one country-specific heading within the broader 9903.05.20 through 9903.05.84 range reserved for the Section 301 Forced Labor program; it is entirely separate from the Section 301 Brazil codes at 9903.05.01 through 9903.05.09.
• This Chapter 99 code rides alongside your regular chapter 1-97 classification line on every affected entry; both codes must appear on the entry summary.

On this page

1. What this code is and who must care
2. Legal authority and program background
3. Product and country scope
4. Rate and effective window
5. How 9903.05.55 stacks with other duties
6. How it appears on a customs entry
7. What importers should do
8. Key references

HTS 9903.05.55 is a Chapter 99 special tariff code that adds 10 percent ad valorem to the dutiable value of all products of Mexico, effective July 24, 2026, under the Section 301 Forced Labor program. Any importer whose goods originate in Mexico, regardless of product category, must add this code to every affected entry summary filed on or after that date. The links throughout this article go directly to the primary documents: the USTR final action, CSMS guidance, and the official tariff schedule. Read the source.

What this code is and who must care

9903.05.55 is a country-specific heading within the Section 301 Forced Labor Investigation (FLIP) action. It applies to importers, customs brokers, and trade compliance teams responsible for goods manufactured in or originating from Mexico across all commodity categories. Because the scope is all chapters 1 through 97, no product type is carved out based on the facts available as of September 9, 2026. Whether you import agricultural goods, manufactured components, finished consumer products, or industrial materials from Mexico, this code applies to your entries.

Do not confuse this code with the Section 301 Brazil program, which uses heading numbers 9903.05.01 through 9903.05.09. The Mexico forced-labor action sits in the 9903.05.20 through 9903.05.84 range, alongside other country-specific forced-labor headings. For comparison, see articles on nearby country codes such as 9903.05.50 Jordan (10%) and 9903.05.45 Indonesia (10%).

Legal authority and program background

The duty is authorized under Section 301 of the Trade Act of 1974, which gives USTR authority to investigate and respond to foreign trade practices that burden U.S. commerce. USTR's Forced Labor Investigation (FLIP) extended that authority to practices involving forced labor in foreign supply chains.

The specific legal instruments governing 9903.05.55 are:

• USTR 301 FLIP final action, July 23, 2026 - the determination triggering the additional duty on Mexican-origin goods.
• U.S. note 52 to Chapter 99 of the HTSUS - the schedule note that defines covered countries and rates for the entire forced-labor action, including this heading.
• CSMS message 69326983 - CBP's operational guidance for brokers and importers filing entries under this action.

Confirm the current text of U.S. note 52 in the Harmonized Tariff Schedule (hts.usitc.gov) and review CBP's guidance at cbp.gov.

Product and country scope

Country

The sole country covered by 9903.05.55 is Mexico (MX). Origin is determined by standard CBP rules of origin; the duty applies to goods whose country of origin is Mexico as declared on the entry.

Products

Under U.S. note 52(a), the heading covers all chapter 1 through 97 products of Mexico. The facts block references migration note [migration_202607281700], which indicates the scope was confirmed at the time the heading was populated in the tariff schedule. No product-specific exclusions are described in the facts available as of September 9, 2026. If you believe a specific product may be excluded, confirm against the current HTSUS or with your broker.

Effective date and duration

Coverage runs from July 24, 2026, onward. No end date has been announced. The duty remains in effect until USTR issues a further determination or the schedule is modified.

Rate and effective window

The additional rate is 10 percent ad valorem, applied on top of whatever duties already apply to the goods under their chapter 1-97 classification. This rate has been in effect since July 24, 2026, with no announced end date as of September 9, 2026.

Rates under the broader Section 301 Forced Labor program vary by country. For example, Kuwait, Kazakhstan, Japan, Israel, Iraq, and Hong Kong each carry 12.5 percent under their respective headings, while Jordan, Indonesia, India, Honduras, and Mexico each carry 10 percent. Confirm the rate for any specific country heading directly in the HTSUS.

How 9903.05.55 stacks with other duties

The 10 percent additional duty under 9903.05.55 is cumulative with other applicable duties. Your total duty obligation on a Mexican-origin entry may include:

• MFN (column 1 general) rate from the chapter 1-97 classification line.
• Any other Section 301 duties that apply to the specific product (for example, duties under separate Section 301 China actions, if the goods are of Chinese origin, would not apply here, but other product-specific actions may).
• The 10 percent Section 301 FLIP duty from 9903.05.55.
• Any antidumping or countervailing duties assessed separately on an AD/CVD order covering the product and country.

The facts block does not describe a cap tied to MFN rates for this heading. If you are uncertain how this duty stacks with another action on your specific product, confirm with your broker or check the current HTSUS notes. Use the duty calculator to model your total landed cost.

How it appears on a customs entry

Chapter 99 codes function as overlays. On an entry summary, you will report two classification lines for each affected product:

1. The regular chapter 1-97 HTS number (for example, 8471.30.0100 for a laptop), with its standard duty rate.
2. 9903.05.55 as a secondary line, carrying the 10 percent additional duty.

CBP's Automated Commercial Environment (ACE) requires both lines to appear on the entry summary. CSMS 69326983 contains CBP's specific filing instructions. Review those instructions and confirm your entry preparation procedures with your ACE software vendor or broker. For a broader explanation of how Chapter 99 overlay codes work, see HTS Chapter 99 Explained: Why Your Product Has Two Codes. For tips on pulling ACE entry summary reports to audit your compliance, see ACE Entry Summary Reports: What Every Importer Should Pull.

What importers should do

• Audit open and recent entries. Review all entries covering Mexican-origin goods with a release date on or after July 24, 2026, to confirm 9903.05.55 was applied. Entries missing the code may require a post-summary correction or protest.
• Update your classification and duty-calculation procedures. Ensure your broker, ERP system, and internal compliance team are applying the 10 percent additional duty to all chapter 1-97 products of Mexico from July 24, 2026, onward. Use the duty calculator to model total landed costs.
• Review CSMS 69326983 and U.S. note 52. Confirm ACE filing instructions and the exact text of the note in the current HTSUS to catch any updates issued after September 9, 2026.
• Monitor for program changes. Because no end date has been announced, track USTR and Federal Register notices for any modification, suspension, or termination of the FLIP action affecting Mexico.

Key references

• Harmonized Tariff Schedule of the United States (hts.usitc.gov) - official schedule including Chapter 99 heading 9903.05.55 and U.S. note 52.
• CBP.gov - home of CSMS message 69326983 and ACE filing guidance for the Section 301 FLIP action.
• Federal Register (federalregister.gov) - search for USTR Section 301 Forced Labor Investigation (FLIP) final action published around July 23, 2026.
• USTR.gov - USTR's Section 301 FLIP final action of July 23, 2026, the determination authorizing the additional duty on products of Mexico.
• Section 301 of the Trade Act of 1974 (law.cornell.edu) - statutory authority for the FLIP action.
• HTS Chapter 99 Explained: Why Your Product Has Two Codes - how Chapter 99 overlay codes appear alongside chapter 1-97 lines on entry summaries.
• ACE Entry Summary Reports: What Every Importer Should Pull - guidance on using ACE reports to audit duty application across your entry portfolio.