USTR Section 301 Exclusion Amendments and ACE HSU 2621: What Importers Must Do

Key Points

• USTR is making conforming amendments to four Section 301 China product exclusions, effective July 1, 2026, driven by USITC statistical reporting changes to the Harmonized Tariff Schedule.
• Importers relying on any of the four amended exclusions must verify that their HTS classifications still correctly map to the revised exclusion language to avoid unexpected duty exposure.
• ACE Harmonized System Update (HSU) 2621, created August 22, 2026, adds 13 harmonized tariff records and 54 ABI records, including Section 338 updates.
• HSU 2621 also changes FSIS PGA flags: the FS3 flag is added to HTS codes 2106.90.9990, 2106.90.9993, and 2106.90.9994, and the FS4 flag on five egg-product HTS codes is updated to FS3.
• AES filers must update country-of-origin references for Nauru, which has officially renamed itself the "Republic of Naoero" under a constitutional amendment.

On this page

1. What changed with the USTR Section 301 conforming amendments
2. Why the HTSUS reclassification triggered the amendments
3. ACE HSU 2621: Section 338 updates and ABI record changes
4. FSIS PGA flag changes in HSU 2621
5. AESTIR Appendix C: Nauru country-code update
6. What importers, brokers, and compliance teams should do
7. Key references

USTR has published conforming amendments to four Section 301 product exclusions covering Chinese goods, with an effective date of July 1, 2026, after the USITC revised statistical reporting categories in the Harmonized Tariff Schedule. Separately, CBP released ACE Harmonized System Update 2621 on August 22, 2026, carrying Section 338 tariff changes, updated FSIS PGA flags, and a country-name correction for Nauru. The links in this article go to the primary documents: the Federal Register notice, CBP CSMS messages, and official agency pages themselves. Read the source.

What changed with the USTR Section 301 conforming amendments

On September 2, 2026, USTR published a Federal Register notice amending four product exclusions granted under the Section 301 investigation into China's acts, policies, and practices related to technology transfer, intellectual property, and innovation. The amendments are conforming in nature, meaning USTR is not changing the substantive scope of the exclusions themselves. Rather, the agency is updating the HTS subheading references within those exclusions to align with new statistical reporting categories that the U.S. International Trade Commission introduced on July 1, 2026.

For importers, a conforming amendment is not a free pass. If your entry or binding ruling references a specific HTS subheading that has been renumbered or split, the exclusion as originally filed may no longer match your product's correct classification. Any mismatch could result in Section 301 duties being assessed where none were intended.

Why the HTSUS reclassification triggered the amendments

The Harmonized Tariff Schedule of the United States is revised periodically by the USITC to reflect changes in statistical reporting needs. When subheadings are split, merged, or renumbered, any regulatory text that references the old numbers, including exclusion orders, must be updated to remain operative. The July 1, 2026 USITC changes affected the four subheadings underlying these exclusions, prompting USTR to publish the conforming amendments retroactively to the same July 1 effective date.

ACE HSU 2621: Section 338 updates and ABI record changes

CBP's CSMS message 69726413, published September 1, 2026, announces that Harmonized System Update 2621 was created in ACE on August 22, 2026. The update contains 13 harmonized tariff records and 54 ABI records. HSU 2621 incorporates the Section 338 tariff updates referenced in the earlier CBP CSMS message 69606660. ABI filers and software vendors should confirm that their systems have ingested all 54 updated ABI records to avoid filing rejections on affected HTS codes.

FSIS PGA flag changes in HSU 2621

HSU 2621 also carries Partner Government Agency flagging changes for the Food Safety and Inspection Service (FSIS):

• FS3 flag added to HTS codes 2106.90.9990, 2106.90.9993, and 2106.90.9994 (food preparations, not elsewhere specified or included).
• FS4 flag updated to FS3 on HTS codes 0407.21.0030, 0408.11.0000, 0408.19.0000, 0408.91.0000, and 0408.99.0000 (eggs and egg products).

Brokers filing entries for food preparations or egg products under these subheadings must ensure their ABI software transmits the correct FSIS message set. An incorrect or missing PGA flag can cause an entry to be held at the port pending FSIS review.

AESTIR Appendix C: Nauru country-code update

CBP's CSMS message 69726210 notifies AES filers that the Government of Nauru passed a constitutional amendment renaming the country the "Republic of Naoero." CBP is updating Appendix C (ISO Country Codes) of the Automated Export System Trade Interface Requirements (AESTIR) accordingly. The updated documentation is available on the CBP AES webpage. Exporters shipping goods to or from Nauru should verify that their AES filing software and internal country-code tables reflect the new official name to avoid Electronic Export Information (EEI) rejections.

What importers, brokers, and compliance teams should do

• Pull every active Section 301 exclusion your company relies on and compare the HTS subheadings cited in those exclusions against the updated HTSUS effective July 1, 2026; flag any that were affected by the USITC reclassification and cross-check against the USTR conforming amendments notice.
• Confirm that your ABI software and tariff database have loaded all 54 ABI records from HSU 2621, paying particular attention to the Section 338 entries and the FSIS PGA flag changes for the food-preparation and egg-product HTS codes listed above.
• Update internal country-code tables and AES filing templates to use the new official name "Republic of Naoero" for Nauru in line with the revised AESTIR Appendix C.

Key references

• Federal Register: USTR Notice of Conforming Amendments to Section 301 Product Exclusions (Sept. 2, 2026)
• CSMS 69726413: Harmonized System Update (HSU) 2621, Section 338 and FSIS PGA flag changes (Sept. 1, 2026)
• CSMS 69726210: Update to AESTIR Appendix C, ISO Country Codes, Nauru name change (Sept. 1, 2026)
• USITC Harmonized Tariff Schedule of the United States
• CBP AES AESTIR Appendix C: Commodity Filing Response Messages