When you see an HTS code starting with “9903” on your customs documents, you’re looking at a Chapter 99 tariff — and if you’re an importer who paid duties during the IEEPA period, those four digits are the key to your refund claim. Chapter 99 is the section of the U.S. tariff schedule where temporary and special tariff actions live, and it’s where both the fentanyl tariffs (9903.01) and the Liberation Day reciprocal tariffs (9903.02) were classified.
Understanding Chapter 99 isn’t just academic. It’s the practical foundation for identifying which of your import duties are IEEPA-related and therefore refundable under the Supreme Court’s ruling. If you can spot Chapter 99 codes on your entry summaries, you can identify your refund claim. If you can’t, you might miss money that’s owed to you.
Let’s start from the very beginning.
What the Harmonized Tariff Schedule Is
The Harmonized Tariff Schedule of the United States (HTSUS) is the official reference document that assigns a tariff classification — and a duty rate — to every product imported into the country. It’s maintained by the U.S. International Trade Commission (USITC) and runs to about 3,700 pages.
The HTS is organized into Sections (broad categories like “Live Animals” or “Machinery”) and Chapters (numbered 1 through 99). Each chapter covers a specific type of product or, in the case of Chapter 99, a specific type of tariff action.
Here’s a simplified overview of the structure:
| Chapters | Coverage |
|---|---|
| 1-5 | Animal products |
| 6-14 | Vegetable products |
| 15 | Fats and oils |
| 16-24 | Food products |
| 25-27 | Mineral products |
| 28-38 | Chemicals |
| 39-40 | Plastics and rubber |
| 41-43 | Leather, hides, furs |
| 44-49 | Wood, paper |
| 50-63 | Textiles |
| 64-67 | Footwear, headwear |
| 68-71 | Stone, glass, jewelry |
| 72-83 | Metals |
| 84-85 | Machinery and electronics |
| 86-89 | Vehicles and transport |
| 90-92 | Instruments, clocks, musical |
| 93 | Arms and ammunition |
| 94-96 | Furniture, toys, misc. |
| 97 | Art and antiques |
| 98 | Special classification (returning goods, etc.) |
| 99 | Temporary tariff actions |
Every product that enters the U.S. gets classified into one of Chapters 1-97 based on what it actually is. A cotton t-shirt goes to Chapter 61. A steel pipe goes to Chapter 73. A laptop goes to Chapter 84. The duty rate in that chapter is the product’s base duty rate — the permanent rate set by Congress.
Chapters 98 and 99 are different. They’re not about what the product is — they’re about special circumstances that modify the duty treatment. Chapter 99, specifically, is the home of temporary modifications to the tariff schedule imposed by the executive branch under various statutory authorities.
How Chapter 99 Works
When the President imposes tariffs under Section 301, Section 232, IEEPA, or other authorities, those tariffs don’t change the base rates in Chapters 1-97. Instead, they’re added as new subheadings in Chapter 99. The product keeps its original classification — a cotton t-shirt is still Chapter 61 — but it also gets an additional Chapter 99 code that imposes an extra duty on top of the base rate.
Think of it like a surcharge on your hotel bill. The room rate (base duty) stays the same. But the hotel adds a resort fee (Chapter 99 tariff) on top. When you check out, you pay both.
Here’s how it looks on an actual import entry:
Example: Importing ceramic tiles from China in July 2025
| Line | HTS Code | Chapter | Description | Rate |
|---|---|---|---|---|
| 1 | 6907.23.10 | 69 | Ceramic tiles, glazed | 8.5% |
| 2 | 9903.88.03 | 99 | Section 301 List 3 tariff | 25% |
| 3 | 9903.01.25 | 99 | IEEPA fentanyl tariff | 20% |
Lines 2 and 3 are both Chapter 99 codes, but they’re imposed under different authorities:
- 9903.88 = Section 301 (Trade Act of 1974) — still in effect
- 9903.01 = IEEPA (International Emergency Economic Powers Act) — struck down, refundable
The importer pays all three lines when the entry is filed. After the Supreme Court ruling, line 3 is refundable. Lines 1 and 2 are not.
This is why understanding Chapter 99 — and specifically which subheadings within Chapter 99 are IEEPA-based — is essential for calculating your refund.
The Key Chapter 99 Subheadings
Chapter 99 contains dozens of subheadings for different tariff actions. Here are the ones that matter for IEEPA recovery:
9903.01 — IEEPA Fentanyl Tariffs
These codes cover the tariffs imposed in early February 2025 under executive orders citing fentanyl trafficking as a national emergency. They applied primarily to imports from:
- China — rates ranging from 10% initially to 60%+ as escalations compounded
- Canada — 25%
- Mexico — 25%
The 9903.01 subheading has multiple sub-codes (9903.01.01 through 9903.01.85 and beyond) depending on the specific product, rate modification, and effective date. All of them are IEEPA-based and all are covered by the Supreme Court ruling.
9903.02 — IEEPA Reciprocal Tariffs (Liberation Day)
These codes cover the “reciprocal” tariffs announced on April 2, 2025, affecting virtually every U.S. trading partner. The rates varied by country:
- 10% baseline for most countries
- 20-50% for countries with larger bilateral trade deficits with the U.S.
- Applied on top of any existing 9903.01 tariffs for China, Canada, and Mexico
Like 9903.01, the 9903.02 subheading has numerous sub-codes. All are IEEPA-based and all are refundable.
Chapter 99 Codes That Are NOT Refundable
Not everything in Chapter 99 is an IEEPA tariff. Here are the subheadings that remain in effect:
- 9903.88 — Section 301 tariffs on China. These were imposed under the Trade Act of 1974, not IEEPA. They cover Lists 1-4 of China tariffs at rates of 7.5-25%. Still in effect, not refundable.
- 9903.80 — Section 232 tariffs on steel and aluminum. Imposed under the Trade Expansion Act of 1962. Still in effect, not refundable.
- Other 99xx codes — Various other trade remedy and preferential program codes that aren’t IEEPA-related.
The critical distinction is the statutory authority, not the chapter. Chapter 99 codes imposed under IEEPA (9903.01 and 9903.02) are refundable. Chapter 99 codes imposed under Section 301 (9903.88) or Section 232 (9903.80) are not. For a detailed breakdown of these codes, see our HTS 9903 codes guide.
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How to Find Chapter 99 Codes on Your Documents
Your IEEPA tariff exposure shows up in several places:
On the CF-7501 (Entry Summary)
The CF-7501 is your primary customs document. Each line item shows an HTS code. Scan the HTS column for any code beginning with 9903.01 or 9903.02. Those are your IEEPA lines. The duty amount on those lines is your refund claim for that entry. Our guide to reading the CF-7501 walks through the form in detail.
On ACE Reports
If your customs broker pulls an ES-003 Entry Summary Details report from the ACE portal, the HTS codes will be listed for every line item on every entry. Filter for 9903.01 and 9903.02 to isolate your IEEPA lines.
On Broker Invoices
Most customs brokers include HTS codes on their invoices or billing statements. While these may not show full 10-digit codes, they usually show enough to identify Chapter 99 lines.
On Commercial Invoices (Sometimes)
Some suppliers include HTS codes on their commercial invoices, though this is less reliable — the supplier’s code may not match what your broker actually classified the product as.
The Layering Effect: How Chapter 99 Stacks
One of the most confusing aspects of Chapter 99 for importers is how multiple tariff layers stack on a single product. Let’s break this down with a concrete example.
Product: Steel fasteners from China Entry date: June 2025
| Layer | HTS Code | Authority | Rate | Status |
|---|---|---|---|---|
| Base duty | 7318.15.20 | Permanent (Congress) | 3.6% | Active |
| Section 232 steel | 9903.80.01 | Trade Expansion Act | 25% | Active |
| Section 301 List 1 | 9903.88.01 | Trade Act of 1974 | 25% | Active |
| IEEPA fentanyl | 9903.01.25 | IEEPA | 20% | Struck down |
On a $100,000 shipment, the duties would have been:
- Base: $3,600
- Section 232: $25,000
- Section 301: $25,000
- IEEPA: $20,000
- Total: $73,600
After the Supreme Court ruling, the IEEPA layer is removed:
- Refundable: $20,000 (plus statutory interest)
- Still owed: $53,600 (base + 232 + 301)
This layering effect is why you can’t just look at total duties paid and assume it’s all refundable. You need to isolate the IEEPA-specific lines. The Chapter 99 subheading codes are how you do that.
For importers sourcing from non-China countries that don’t carry Section 301 or Section 232 duties, the math is simpler. If your Vietnamese imports had a 46% IEEPA reciprocal tariff and no other Chapter 99 tariffs, then 100% of your Chapter 99 duty is refundable.
Chapter 99 and the Recovery Process
Understanding Chapter 99 codes is directly relevant to each recovery path:
Post-Summary Correction
When your broker files a PSC for an unliquidated entry, they’re specifically removing the 9903.01 or 9903.02 tariff lines from the entry. The base duty lines and any non-IEEPA Chapter 99 lines remain. CBP recalculates the total duty without the IEEPA lines and refunds the difference.
Formal Protest
A protest for a liquidated entry argues that the liquidation was incorrect because it included duty under tariff codes that have been invalidated. The protest references the specific 9903.01 or 9903.02 codes and requests reliquidation without those lines. The 180-day protest window runs from the date of liquidation.
CIT Litigation
Court filings for entries outside the protest window similarly identify the specific Chapter 99 codes at issue. The legal argument is straightforward given the Supreme Court ruling, but the court process is more involved.
Claim Valuation
When valuing a refund claim for potential assignment, the precise Chapter 99 codes and duty amounts are the foundation of the calculation. The more precisely you can identify your IEEPA lines, the more accurately your claim can be valued. An Impact Assessment performs this analysis across your entire entry portfolio.
Frequently Asked Questions About Chapter 99
Q: If my product has a base duty of 0%, do I still have an IEEPA refund claim?
Yes. Many products — especially electronics and technology — have a 0% base rate but were still subject to IEEPA tariffs through Chapter 99 codes. If your entry has a 9903.01 or 9903.02 line, the duty on that line is refundable regardless of the base rate.
Q: How do I tell the difference between a Section 301 code and an IEEPA code?
Look at the four digits after “9903.” Section 301 codes use 9903.88 (the .88 subheading). IEEPA fentanyl codes use 9903.01. IEEPA reciprocal codes use 9903.02. Section 232 codes use 9903.80. If you encounter unfamiliar codes, the IEEPA tariff refund glossary is a helpful reference.
Q: Can a single entry have both Section 301 and IEEPA codes?
Absolutely. Entries for Chinese goods commonly have both 9903.88 (Section 301) and 9903.01 (IEEPA fentanyl) lines. Only the 9903.01 line is refundable.
Q: What if I’m not sure which codes are on my entries?
Your customs broker can pull this data from the ACE system. Alternatively, request an Impact Assessment and we’ll identify every IEEPA line across all your entries.
Q: Do Chapter 99 codes affect my product’s country of origin?
No. Chapter 99 codes are supplementary tariff lines — they don’t change the underlying classification or origin of your product. Your product remains classified under its original Chapter 1-97 code. The Chapter 99 code is an additional duty line applied on top.
What This Means for Your Refund
Chapter 99 is the roadmap to your IEEPA money. If you can identify the 9903.01 and 9903.02 codes on your entries, you can quantify your claim. Here’s the process:
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Pull your entry data. Ask your broker for CF-7501s or ACE reports covering February 2025 through February 2026.
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Scan for IEEPA codes. Look for HTS codes starting with 9903.01 or 9903.02.
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Sum the duty amounts. Add up the dollar amounts on all IEEPA lines across all entries.
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Add interest. Statutory interest at approximately 4-5% annually accrues from payment date to refund date.
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Check for eligibility. Confirm you’re the importer of record on these entries.
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Map to recovery paths. Each entry’s liquidation status determines the available path.
The Future of Chapter 99
The Supreme Court’s IEEPA ruling removed the 9903.01 and 9903.02 subheadings from active enforcement, but Chapter 99 itself continues to be a living document. Here’s what to expect going forward:
Existing Chapter 99 tariffs continue. Section 301 tariffs on China (9903.88), Section 232 tariffs on steel and aluminum (9903.80), and other non-IEEPA Chapter 99 actions remain in effect. These were imposed under proper statutory authority and weren’t affected by the ruling.
New Chapter 99 subheadings may appear. If Congress passes new tariff legislation, or if the administration takes tariff actions under Section 301 or Section 232, those new tariffs would be added to Chapter 99 with new subheadings. The chapter is designed to accommodate these changes.
IEEPA subheadings will be removed. At some point, the USITC will formally remove the 9903.01 and 9903.02 subheadings from the HTS, since the underlying authority for those tariffs has been invalidated. This is an administrative action that formalizes what the Supreme Court already decided.
Classification records remain important. Even after the IEEPA subheadings are removed from the HTS, the historical records of entries that included those codes remain in ACE. These records are the basis for your refund claim and should be preserved.
For importers, the practical lesson from Chapter 99 is to always understand which statutory authority is behind each tariff line on your entries. Not all Chapter 99 tariffs are created equal, and the next time trade policy shifts, knowing the difference between a Section 301 code and an IEEPA code could be worth millions.
If you want this done comprehensively — every entry identified, every IEEPA line isolated, every deadline mapped — request an Impact Assessment. We’ve processed millions of HTS lines and know exactly where to look for the Chapter 99 codes that matter. Consult our beginner’s guide if you’re just getting started with the recovery process.
