Chapter 99 of the Harmonized Tariff Schedule of the United States (HTSUS) is where temporary and additional tariff measures are written into the tariff: Section 301 duties, Section 232 duties, safeguards, temporary duty suspensions and the exemptions from all of these. A Chapter 99 line never describes a product on its own. Each 9903 heading points back to products classified in Chapters 1–97, usually through a U.S. note that lists the subheadings and the countries covered, and its rate column tells you whether the measure adds to the normal duty, replaces it, or leaves it unchanged. On the entry, the 9903 number is reported on the same line as the product’s normal 10-digit number, and several 9903 numbers can sit on one line when measures stack.
The rest of this article shows how to read those lines and how to tell whether two measures add up, exclude each other, or set a combined rate.
Why Chapter 99 exists
Chapters 1–97 are the US version of the international Harmonized System, extended to 8-digit tariff lines and 10-digit statistical lines. Their rates change only through the formal processes for amending the tariff. Trade statutes, though, let the President or the US Trade Representative change the duty on particular goods for particular periods. Section 301 of the Trade Act of 1974 (19 U.S.C. 2411) lets USTR impose duties in response to foreign practices it finds actionable. Section 232 of the Trade Expansion Act of 1962 (19 U.S.C. 1862) lets the President adjust imports that threaten national security.
Those actions have to appear in the tariff somewhere. Under 19 U.S.C. 2483, the President “shall from time to time, as appropriate, embody in the Harmonized Tariff Schedule” the substance of such actions, “including removal, modification, continuance, or imposition of any rate of duty or other import restriction.” Chapter 99 is where that happens. It keeps the product classification in Chapters 1–97 stable and puts the temporary layer beside it.
Chapter 99 is a US provision with no counterpart in the international HS. It is not a classification chapter: you never classify a product “in” 9903 by applying the General Rules of Interpretation. You classify it in Chapters 1–97 first and then check whether a Chapter 99 provision refers to that classification.
The parts of Chapter 99 you will meet most
Chapter 99 is divided into subchapters, each with its own U.S. notes. Two matter most in daily entry work:
- 9902 lines hold temporary duty suspensions and reductions, the product-specific lines created by miscellaneous tariff legislation. Each describes a narrowly defined product, names the Chapter 1–97 subheading it falls in and has an effective period; while that period runs, its rate replaces the normal rate. 9902.16.20, for example, describes a tightly defined type of rechargeable lithium battery “provided for in subheading 8507.60.00” and gives it a Free rate. Check the effective period of any 9902 line against your entry date before relying on it.
- 9903 lines in subchapter III hold the additional duties and their exemptions: Section 301 actions on China and on other economies, Section 232 actions on metals and other sectors, and others. Each action has its own U.S. note to the subchapter that defines scope, exceptions and conditions.
One consequence of a 9903 line shows up in 19 CFR 143.21(a): the usual $2,500 limit for informal entry does not apply to articles valued over $250 that are classified in Chapter 99, Subchapters III and IV. Goods with an additional duty can need a formal entry at a much lower value.
How to read a 9903 line
Every 9903 line has three parts that work together: the article description, the reference to a U.S. note, and the rate column. Take a real example from the current HTSUS:
9903.88.03: “Except as provided in” a list of other 9903.88 headings, “articles the product of China, as provided for in U.S. note 20(e)” to subchapter III and the subheadings enumerated in U.S. note 20(f). General rate: “The duty provided in the applicable subheading + 25%”.
Read it in this order.
- Origin: “the product of China.” The measure applies by country of origin, not country of export.
- Product scope: “as provided for in U.S. note 20(e)” and the subheadings in note 20(f). The note lists Chapter 1–97 subheadings. If your 8-digit line is not listed, the heading does not apply, however similar the product looks.
- Exceptions: “Except as provided in headings …” The listed headings are mostly product exclusions. If your goods meet the description of an exclusion heading, you report that heading instead.
- Rate: “The duty provided in the applicable subheading + 25%.” The measure adds 25 percent of value to whatever the Chapter 1–97 line charges.
The phrasing follows the same logic as the legal phrases in the nomenclature itself (“except as provided”, “other than”, “provided for in”), and reading it with the same discipline avoids most errors. For the general reading habits, see the legal phrase patterns in the Harmonized System.
Three ways a rate column can be written
The rate column is where people most often go wrong. In the current Chapter 99 there are three distinct forms, and they mean different things:
| Rate column says | Effect | Example in the current HTSUS |
|---|---|---|
| “The duty provided in the applicable subheading + X%” | Adds X% to the normal rate | 9903.05.44, products of India under U.S. note 52: subheading + 10% |
| A flat “X%” | Sets a combined rate of X% in place of the normal rate | 9903.05.39, products of an EU member state whose column 1 rate is below 10%: 10% |
| “The duty provided in the applicable subheading” or “No change” | No additional duty; the line records an exemption or a case where the measure adds nothing | 9903.05.90, articles covered by U.S. note 52(f) (aluminium, steel, copper and derivatives, vehicles and parts, wood, patented pharmaceuticals, semiconductors) |
The flat-rate form is easy to misread as “add 10 percent.” It is not. For an EU-origin product with a 2.5 percent column 1 rate, 9903.05.39 makes the total 10 percent, so the Section 301 measure adds 7.5 points. For an EU-origin product whose column 1 rate is already 10 percent or more, 9903.05.38 applies and the rate column reads “the duty provided in the applicable subheading,” so nothing is added.
How 9903 lines attach to an entry line
A single entry line can carry several HTS numbers. CBP’s published guidance on the order of reporting multiple HTS numbers in ACE sets this sequence:
- Chapter 98 number, if one applies.
- Chapter 99 numbers for additional duties.
- Trade remedy numbers: Section 301 first, then the Section 232 or 201 duty number, then any Section 232 or 201 quota number.
- Chapter 99 numbers for replacement duties or other uses (for example, a 9902 temporary reduction).
- Any other quota number.
- The Chapter 1–97 number, last.
The entered value is reported against the Chapter 1–97 number. CBP’s page was last updated in August 2023, and each new action comes with its own CSMS filing instructions, so check the guidance issued for the measure you are filing.
In practice, the 9903 number is what some brokers call the “secondary” HTS number. Leaving it off does not remove the duty. It produces an underpaid entry.
Do the measures stack?
Stacking is decided by the notes and heading descriptions, measure by measure. There is no general rule that all additional duties add up, and none that the highest one wins. Three patterns appear.
Additive. Two measures both apply and their rates are added to the normal duty. On the heading texts, USTR’s forced-labour Section 301 duty and the earlier Section 301 duties on products of China work this way: 9903.05.31 (products of China, subheading + 12.5%) carves out only its own exemption headings (9903.05.85 to 9903.05.92), and the “except as provided” list in 9903.88.03 names only other 9903.88 headings. Neither heading excludes goods covered by the other.
Mutually exclusive. One measure’s notes exempt goods covered by another. The forced-labour action does this for Section 232 goods: articles under U.S. note 52(f), which names aluminium, steel and copper and their derivatives, vehicles and parts, wood, patented pharmaceuticals and semiconductors, go to the exemption heading 9903.05.90 at “the duty provided in the applicable subheading.” The temporary Section 122 surcharge that applied from 24 February to 24 July 2026 likewise did not apply to goods subject to Section 232 duties, and where Section 232 covered only part of an article it applied only to the rest.
Combined rate. Some lines set a total in place of the normal rate, as with the EU, Taiwan, Japan, South Korea and Switzerland lines in the forced-labour action (for example 9903.05.49 for Japanese goods with a column 1 rate below 12.5 percent: 12.5 percent). Section 232 lines use the same device; the current 9903.82 headings include lines written as “10%” or “15%” for some derivative articles and “No change” for others, depending on the column 1 rate.
Two more points decide the arithmetic:
- Each percentage is normally applied to the same customs value, the transaction value under 19 U.S.C. 1401a. Rates are added; they do not compound. A 3 percent base rate with additional duties of 25 percent and 12.5 percent is 40.5 percent of value, not 1.03 × 1.25 × 1.125.
- Exclusions and exemptions have conditions. An exclusion heading often describes the product more narrowly than the subheading. If the goods do not meet every element of that description, the exclusion does not apply, and you need records showing that they do.
One subheading, four origins
The effect of these drafting choices is easiest to see on one product. Take cotton terry bath towels, HTSUS 6302.60.00.20, column 1 general rate 9.1 percent, and the forced-labour Section 301 lines in force for entries from 24 July 2026, as the HTSUS showed them in October 2026. CBP’s exemption list issued with CSMS #69326983 on 23 July 2026 does not list 6302.60.00 under the general, particular-article or EU exemption headings, so the economy lines apply. The table ignores other measures; it shows how the rate columns work and is not a duty determination for any entry.
| Origin | Chapter 99 line | Rate column | Total ad valorem duty |
|---|---|---|---|
| India | 9903.05.44 | Subheading + 10% | 9.1% + 10% = 19.1% |
| China | 9903.05.31 | Subheading + 12.5% | 9.1% + 12.5% = 21.6%, plus any China Section 301 list duty if 6302.60 is enumerated in note 20 |
| An EU member state | 9903.05.39 (column 1 rate below 10%) | 10% | 10% |
| Japan | 9903.05.49 (column 1 rate below 12.5%) | 12.5% | 12.5% |
The same classification gives four different results because the rate columns are drafted differently. Anyone who adds the “headline” 10 or 12.5 percent to the 9.1 percent for every origin gets the EU and Japanese rows wrong, because those lines set a total instead of adding to the normal rate. The duty arithmetic for a full entry, including MPF and HMF, is set out in how to calculate US import duty, and the full landed-cost checklist puts the duty in context with freight and service charges.
Status as of October 2026
Chapter 99 changes more often than any other part of the HTSUS. As of October 2026:
- The forced-labour Section 301 action (USTR notice, 91 FR 47318) covers products of 60 economies through 9903.05.20 to 9903.05.84 under U.S. note 52, for goods entered on or after 12:01 a.m. EDT on 24 July 2026, with exemption and special headings from 9903.05.85 onward. Goods subject to it that are admitted to a foreign-trade zone, other than those eligible for domestic status, may be admitted only in privileged foreign status. CBP’s filing guidance is CSMS #69326983 of 23 July 2026, with the HTS lists for the exemption headings.
- Section 232 duties on aluminium, steel and copper and their derivatives are reported under 9903.82 headings referring to U.S. note 16, among other 232 actions.
- The Section 301 duties on products of China under U.S. note 20 (9903.88 headings) and the later modifications under U.S. note 31 (9903.91 headings) continue, with product exclusions that have their own expiry dates.
- The Section 122 surcharge ended at 12:01 a.m. EDT on 24 July 2026 (Proclamation 11012). IEEPA duties were collected on entries up to 24 February 2026; the Supreme Court had held on 20 February 2026 that IEEPA does not authorise tariffs, and CBP is building a refund process in ACE to carry out the Court of International Trade’s refund orders (CBP notice, 91 FR 63299). Both remain relevant for entries made while they applied, including liquidation, protests and refunds.
Always use the HTSUS edition in force on the date of entry. The USITC keeps prior editions online, and a duty question about an older entry has to be answered with the schedule and notes that applied then.
A checking routine for any product
- Classify the product in Chapters 1–97 from its facts, using the GRIs and the Section and Chapter Notes. A Chapter 99 answer can never be better than the classification under it, which is why HS classification mistakes carry straight through to Chapter 99 errors.
- Fix the country of origin under the rules that apply to the measure. Some measures use special origin language (the Russian-aluminium lines in 9903.85, for example, refer to where the metal was smelted or cast).
- Search Chapter 99 for every heading whose note lists your 8-digit subheading, and for every heading that applies to your origin regardless of product.
- For each candidate, read the heading’s “except as provided” list and the exemption headings that point back to it. Decide which applies and record why.
- Read the rate column literally: added, combined, or no change.
- Check the effective date, the in-transit rule and any expiry for each line against your date of entry.
- Keep the result, the note text and the date you checked it in the product’s classification file.
Questions people ask
My product’s general rate is “Free”. Can it still owe Chapter 99 duty?
Yes. A Free rate in column 1 is the normal duty only. Under a “subheading + X%” line the result is simply X percent of value, and under a flat combined-rate line the full combined rate applies.
Can I classify a product directly in a 9903 heading?
No. A 9903 heading does not describe goods by their nature; it applies a measure to goods already classified elsewhere. The Chapter 1–97 number is always reported, and it carries the entered value.
Does a Chapter 99 duty change the HS code my supplier or other countries use?
No. Chapter 99 is a US-only layer. The six-digit HS subheading and the foreign tariff lines stay the same; only the US duty treatment changes.
Questions about which 9903 lines apply to a specific product usually come down to the classification underneath and the wording of the notes. Surajit Roy works on HS and HTS classification questions and can be reached through the contact page.
Sources
- USITC: Harmonized Tariff Schedule of the United States, Chapter 99 lines 9903.05, 9903.82, 9903.85, 9903.88, 9903.91, 9902.16
- 19 U.S.C. 2411, Section 301 actions by the United States Trade Representative
- 19 U.S.C. 1862, Safeguarding national security (Section 232)
- 19 U.S.C. 2483, Embodiment of actions in the Harmonized Tariff Schedule
- 19 CFR 143.21, Merchandise eligible for informal entry
- CBP: Order of reporting multiple HTS numbers in ACE
- USTR, Notice of Actions in Section 301 Investigations (forced labor), 91 FR 47318
- CBP, Section 301 Forced Labor HTS List (exemption lists issued with CSMS #69326983, 23 July 2026)
- CBP, Court-Ordered Refunds Under the International Emergency Economic Powers Act Worksheet (5 October 2026, 91 FR 63299)
- Proclamation 11012, Imposing a Temporary Import Surcharge, 91 FR 9339
- Supreme Court, Learning Resources, Inc. v. Trump, No. 24-1287 (20 February 2026)
This article explains the law and practice in general terms. It is not legal advice on a specific product or shipment; for that, check the current official sources or ask a qualified adviser.