How the 2026 tariff layers actually stack: CBP's real sequence, and the myths to unlearn

The short answer: the 2026 tariff layers add, they don’t compound. Each Chapter 99 duty is ad valorem on the entered value, and CBP’s published “sequence” is an order for reporting HTS numbers on the entry line, not a calculation cascade. The things that actually change your bill are the carve-outs: Chapter 98 treatment, the Section 232 exemptions, and the handful of net-of-MFN countries. Here’s the whole picture, from the primary documents.

The sequence people are circulating is garbled

A version of “CBP’s stacking order” has been going around trade circles, often dated late August and listing Section 338 in the middle. The real document is five weeks older and reads differently in the decisive slot. CBP’s guidance is in CSMS #69326983 (July 23, 2026), and its “HTSUS Sequence” block says, for “the order of reporting the HTSUS on an entry summary line”:

1. Chapter 98 (if applicable)
2. Chapter 99 number(s) for additional duties (if applicable)
3. For trade remedies: first the Chapter 99 HTSUS for Section 301, followed by Section 122, followed by Section 232, followed by Section 201 duties, followed by Section 201 quota (each if applicable)
4. Chapter 99 number(s) for replacement duty or other use (e.g. Miscellaneous Tariff Bill)
5. Chapter 99 number for other quota
6. Chapter 1 to 97 commodity tariff

Two corrections to the rumor, then. The third trade-remedy slot is Section 122 (the balance-of-payments surcharge that ran February to July), not Section 338. And Section 338 can’t be in this sequence yet: the current tariff schedule (Revision 17) contains no Section 338 headings at all, because the proclamation annexes were published as images and CBP hasn’t yet issued the implementing notice assigning numbers.

Why “reporting order” versus “cascade” is not pedantry

The same CSMS says the entered value is reported on the Chapter 1-97 line. Each Chapter 99 layer is then assessed ad valorem against that entered value. Nothing applies to a running subtotal, so a product facing a 12.5% layer and a 25% layer owes 37.5 points of additional duty, not 12.5% compounded with 25%. If someone quotes you a landed cost built on multiplication, the math is wrong in your favor to fix.

The rules that actually change the number

The order doesn’t move money; the carve-outs do. Three are in black and white:

• Chapter 98 beats the forced-labor duty, mostly. Goods properly entered under Chapter 98 escape the July 2026 Section 301 duties, except under 9802.00.40/.50/.60 (duty attaches to the value of repairs or processing) and 9802.00.80 (duty attaches to the assembled value less U.S. components).
• Section 232 beats the forced-labor duty. Heading 9903.05.90 exempts goods already covered by the major 232 programs (steel/aluminum/copper, vehicles and parts, medium and heavy trucks, wood products, semiconductors) from the new 301 duties.
• Section 232 beats Section 338 too. All three Canada proclamations say the 50% “shall not apply to articles subject to duties pursuant to section 232,” and civil-aircraft-agreement articles (other than drones) are also out.

Read together: on any given article, check 232 coverage first, because it displaces both of the newer layers.

The July 2026 Section 301 action, from the rate columns

Sixty economies, effective 12:01 a.m. ET July 24, 2026 (the in-transit window closed July 28, so that relief is history). The detail commentary keeps garbling is additive versus net-of-MFN:

• Net-of-MFN, exactly five economies: the EU and Taiwan (combined floor of 10%) and Japan, South Korea, and Switzerland (12.5%). If the normal duty already meets the floor, no additional duty; if it’s below, the schedule applies a flat combined rate.
• Everyone else is additive, including China: heading 9903.05.31 reads “the duty provided in the applicable subheading + 12.5%.” There is no flat “37.5% China rate” anywhere in the primary documents. China’s legacy List 1-4 duties remain separately in force across 66 tiered headings, so total China exposure is a per-HTS-number computation, full stop.
• Four economies got tariff-rate quotas instead: Bangladesh, Cambodia, Indonesia, and Malaysia, with an initial duration of 3 years, structured to encourage those economies to import U.S. cotton and textile inputs. The quota volumes sit in image annexes and aren’t publicly extractable.

A worked example: quartz from China

Take an agglomerated quartz slab, HTS 6810.99.00.20, product of China, entered today. The normal Chapter 1-97 duty is Free, so the Chapter 99 layers are the entire bill:

Layer	Heading	Rate
Section 301 forced labor (China)	9903.05.31	+ 12.5%
Section 201 quartz safeguard, within quota	9903.45.30	25%
Section 201 quartz safeguard, over quota	9903.45.31	50%
Chapter 1-97 (carries entered value)	6810.99.00.20	Free

Within quota, that’s 37.5 points of duty on entered value; over quota, 62.5. Both before any legacy-List or other layer that may attach to this specific subheading, which is a per-shipment check, not an assumption. The safeguard took effect August 15, 2026, runs four years, and excludes eleven countries and country groups (Canada, Mexico, Korea, and others) outright.

Where Canada actually stands

Proclamations 11046, 11047, and 11048 imposed an additional 50% (the statutory ceiling under Section 338) on Canadian alcoholic beverages, dairy, and motor vehicles. Then came the part everyone reads backwards: Proclamation 11056 is titled a temporary suspension, and its preamble talks about “suspending for a period of 3 days,” but its operative clause simply moved the start date: “The effective date of the additional ad valorem duties imposed in Proclamations 11046, 11047, and 11048 shall be 12:01 a.m. eastern time on August 22, 2026.”

So as of August 30, 2026: the duties are on, and have been since August 22. Two practical notes. Entries from August 19-21 that were assessed the 50% may be owed refunds (the proclamation defers to “CBP’s standard procedures,” with no specific mechanism published). And because no Chapter 99 heading for these duties has been published in the tariff schedule or the Federal Register, filers should check the latest CBP messages before transmitting affected entries rather than guessing a number. This is an active negotiation with Canada; the status can move again.

The honest unknowns

A broker’s checklist of what the primary record does not answer yet:

• How Section 338 and the Section 301 forced-labor duty interact on the same non-USMCA Canadian good. Each instrument carves out Section 232; neither mentions the other.
• The Chapter 99 numbers for the Canada duties (pending a CBP Federal Register notice).
• The mechanics of August 19-21 refunds.
• The quartz TRQ volumes (image annex only).

And two dates to calendar: Section 232 duties on unmanned aircraft systems take effect September 3, 2026 (100% for listed UAS and critical components, 25% for a second annex), and Section 232 on polysilicon follows December 4, 2026.

What to do while the guidance is incomplete

On any entry line where two programs could plausibly attach, we cite the primary instruments in the entry file and document the reasoning at filing time. When the missing pieces land (heading numbers, refund mechanics, the 338/301 interaction), a documented position converts cleanly; an undocumented one becomes a post-summary correction project. If you want to see how the current layers price out on your product, the tariff simulator runs the live rates, and we’re happy to walk an entry with you.

Current as of August 30, 2026. Tariff actions this year change on days’ notice; date-check anything here before relying on it.

Sources

• CBP CSMS #69326983, “GUIDANCE: Section 301 Forced Labor Import Duties” (July 23, 2026)
• USTR notice, 91 FR 47318 (July 28, 2026)
• Proclamations 11046-11048 (91 FR 46639, 46653, 46663) and Proclamation 11056, 91 FR 54789
• Proclamation 11051 (quartz safeguard), 91 FR 50645
• USITC Harmonized Tariff Schedule, Revision 17 (2026), Chapter 99