Importers treat the Harmonized Tariff Schedule like a reference book. It is a publication with revisions, and 2026 has already had several that matter. On July 1, 2026, the U.S. International Trade Commission revised some of the 10-digit statistical reporting numbers in the HTSUS. On September 2, 2026, USTR amended four Section 301 exclusions to reflect changes to the tariff schedule, published at 91 FR 56538. The current text sits in HTSUS 2026 Revision 22, and the Chapter 99 U.S. notes are where the additional duties actually live. A rate you verified in January is a rate you verified in January.
The revision that bites hardest is the statistical suffix change. Section 301 list membership is set at the eight-digit subheading, but exclusions are often written against a 10-digit statistical reporting number, and 152 of the 178 active exclusions cover only the product their written description names, so the code alone is not enough. When USITC revises the suffix, an exclusion claim that matched in June can fail in July for no reason visible on the invoice. Checking whether a product qualifies for an exclusion starts with the description, not the number, and the description is what changed.
The first place is the exclusion claim. If your entry claims heading 9903.88.69 or 9903.88.70 and the statistical number underneath it moved, CBP can deny the claim and assess the full list duty: an additional 25 percent for Lists 1, 2, and 3, or 7.5 percent for List 4A. The second place is the Chapter 99 notes themselves. U.S. note 20 sets the Section 301 rates, note 31 and note 52 carry other actions, and the forced-labor Section 301 action added a further 12.5 percent on products of China since July 24, 2026, under heading 9903.05.31. The third place is the entry summary: a line that was correct when the goods shipped can be wrong when they arrive, and the entry date governs.
The practical consequence is that landed cost quotes go stale faster than they used to. A quote built on the January schedule, for goods entering in November, can be off by the full list duty on one line. The fix is not a better spreadsheet. It is a recheck habit: pull the current HTSUS text at hts.usitc.gov for the intended entry date, read the Chapter 99 notes for that line, and have a licensed customs broker confirm the result before the goods ship. That check takes ten minutes and it is the difference between a margin and a surprise.
Start with the 10-digit line on the commercial invoice and confirm it still exists in the current revision. Then read the Chapter 99 U.S. notes that apply to it, not just the column 1 rate. Then check whether any exclusion covers the product as described, and whether that exclusion is still in force for the entry date. If the entry is already filed and the schedule changed underneath it, ask your broker about a Post Summary Correction while the PSC window is open. A correction filed in the window is paperwork. A correction discovered at liquidation is a penalty discussion.
The other habit is watching the Federal Register notices that move the schedule. USTR does not publish a searchable database of active exclusions. The official list is the annexes to the Federal Register notices that granted and extended them, and the December 2025 extension notice contains the current set. Section 321 is gone, and the entry that replaced it is the same lesson in a different chapter: the rule you learned last year is not the rule in force today, and the notice is the only source that counts. The EU low-value parcel fee that started November 1 is the same pattern on the other side of the Atlantic.
More often than most importers check. USITC issues revisions through the year, and 2026 has already seen statistical reporting number revisions on July 1 and USTR amendments to four Section 301 exclusions on September 2. The current text is HTSUS 2026 Revision 22.
The 10-digit code is the 8-digit subheading plus a two-digit statistical suffix. Section 301 list membership is set at the eight-digit level, but many exclusions are written against the full 10-digit number and its description, so a suffix change can break a claim.
At hts.usitc.gov, reading the Chapter 99 U.S. notes for your line on the intended entry date. USTR does not publish a searchable database of active exclusions, so the Federal Register notices are the governing text.
CBP denies the claim and assesses the full list duty for the product: 25 percent for Lists 1, 2, and 3, or 7.5 percent for List 4A. If the entry is still in the PSC window, a Post Summary Correction can fix it.