Substantial transformation and country of origin for assembled goods

Short answer: When a product is assembled in one country from parts made in others, U.S. Customs and Border Protection (CBP) treats it as a product of the last country where it was substantially transformed into a new and different article with a name, character or use distinct from the parts (19 CFR 134.1(b) for marking, 19 CFR 177.22(a) for government procurement). CBP decides this case by case, weighing where the components came from, how much processing happened in each country, and whether that processing produced a new article. Two sets of written rules replace the test in specific situations: the 19 CFR Part 102 tariff-shift rules for marking goods of Canada and Mexico, and 19 CFR 102.21 for textiles and apparel.

Origin questions land on trade teams in two ways: a sourcing plan that moves final assembly to a new country, or a CBP Form CF-28 (Request for Information) asking why an entry says “Vietnam” when the bill of materials says “China”. Both need the same analysis. This guide explains the test as CBP and the courts apply it, when Part 102 takes over, how textiles differ, and what recent CBP determinations on assembled electronics and machinery actually decided. Preferential origin under free trade agreements is a different body of rules, covered in our USMCA rules of origin guide.

Why does country of origin matter beyond the label?

Country of origin decides more than the marking on the box. Section 301 duties apply to products of named countries, so origin picks which Chapter 99 line, if any, goes on the entry: the China Section 301 lists, or the 2026 forced-labor Section 301 duty, which as of October 2026 applies at 10% or 12.5% to goods of 60 economies depending on the country. Antidumping and countervailing duty orders also attach to products of named countries, and evading them through false origin claims is what the Enforce and Protect Act process under 19 USC 1517 investigates. Federal procurement under the Trade Agreements Act depends on origin too; CBP answers those questions in final determinations published in the Federal Register, and several appear in the table below.

Some measures do not follow substantial transformation. Section 232 metals duties apply to covered articles whatever their country of origin (only the rate varies by country), and CBP’s entry guidance asks for the country where the steel was melted and poured. FTA preference follows each agreement’s own rules of origin. Keep the questions separate: one product can be “made in Taiwan” for marking and Section 301, carry Section 232 duty as a listed steel derivative, and fail to qualify for any FTA.

Substantial transformation: name, character and use

Substantial transformation is the judge-made test that asks whether processing turned the inputs into a new and different article of commerce. The phrase “name, character or use” traces back to Anheuser-Busch Brewing Ass’n v. United States, 207 U.S. 556 (1908), and CBP’s regulations repeat it. The procurement definition in 19 CFR 177.22(a) says an article with foreign materials is a product of a country only if it was “substantially transformed into a new and different article of commerce” there, “with a name, character, or use distinct from that of the article or articles from which it was so transformed.”

CBP’s recent final determinations describe the method in almost identical words: the origin of the components, the extent of the processing in each country, and whether that processing renders a product with a new name, character and use are the primary considerations, and design work, post-assembly testing and worker skill are also weighed. No single factor controls. In practice most of the analysis is about character. CBP asks which component or subassembly gives the finished product its function, and where that component was made. For electronics the answer is usually the main printed circuit board assembly (PCBA), and sometimes the place where its firmware or software was written and loaded, which CBP has weighed both ways.

How do courts weigh the factors?

The courts treat substantial transformation as a judgment on the whole set of facts, not a checklist where one “yes” decides the case. Texas Instruments v. United States, 681 F.2d 778 (CCPA 1982), called it a “mixed question of technology and customs law”. The decisions CBP cites most often push in a consistent direction:

• Energizer Battery, Inc. v. United States, 190 F. Supp. 3d 1308 (CIT 2016), involved LED flashlights assembled in the United States from components that were all Chinese except the LED and a hydrogen getter. The court said courts have been reluctant to find a change in character where post-importation processing is assembly, particularly when the parts undergo no physical change, and that a use fixed at the time of import generally means no change in use. It also looked at whether the assembly was simple or complex. The US assembly did not make the flashlights American.
• Uniroyal, Inc. v. United States, 542 F. Supp. 1026 (CIT 1982), aff’d 702 F.2d 1022 (Fed. Cir. 1983), held that attaching imported shoe uppers to outsoles in the US did not substantially transform the uppers.
• National Hand Tool Corp. v. United States, 16 CIT 308 (1992), aff’d 989 F.2d 1201 (Fed. Cir. 1993), is cited for the rule that a predetermined end use generally means no change in use.
• Data General v. United States, 4 CIT 182 (1982), went the other way: programming a foreign PROM chip in the US substantially transformed it, because programming gave the chip its function.

Read together, the cases say that screwing finished parts into a housing rarely moves origin, while making the functional core of the product (building the board, programming it, machining a casting into a working part) often does. CBP has also long held that complex surface-mount assembly of a circuit board from many components is a substantial transformation (C.S.D. 85-25, 1985), while attaching wires to a finished PCBA and putting it in a case is not (HQ 561232, April 20, 2004). Neither 19 CFR 134.1 nor 177.22 sets a percentage of value added that confers origin, and none of the decisions discussed here turned on one; cost appears only as one fact among others.

When do the Part 102 rules apply instead?

The Part 102 rules apply instead of substantial transformation when the question is the marking of a good of Canada or Mexico. The last sentence of 19 CFR 134.1(b) says so directly: for a good of a NAFTA or USMCA country, “the marking rules set forth in part 102” determine the country of origin. Section 102.0 lists the purposes the rules serve, including USMCA marking and certain determinations under the Morocco and Bahrain agreements.

Part 102 replaces judgment with a hierarchy written in HTS terms (19 CFR 102.11). A good is from the country where it was wholly obtained or produced; or where it was produced only from domestic materials; or where each foreign material underwent the tariff shift listed for the good’s subheading in 102.20. If none of those works, origin goes to the country of the single material that gives the good its essential character, and there are further fallbacks for sets, minor processing and simple assembly.

The scope section of Part 102 does not mention Section 301. In HQ H344538 (September 11, 2025), CBP decided the Section 301 origin of a transmission fluid pump made in Canada from Chinese castings by applying substantial transformation case law, without reference to Part 102. That means a good processed in Mexico or Canada can be marked under one test and assessed for additional duties under another, and the two answers can differ.

How is origin decided for textiles and apparel?

Textile and apparel products follow 19 CFR 102.21 for all customs purposes, whatever the country (Israel has its own rule in 102.22), and the section applies to goods entered on or after July 1, 1996. The rule is a sequence. Origin is the single country where the good was wholly obtained or produced; failing that, the single country where each foreign material made the tariff shift listed in 102.21(e); failing that, where a knit-to-shape good was knit or where the good was wholly assembled; and failing that, the country of the most important assembly or manufacturing process, then the last important one.

For many multi-component garments of Chapters 61 and 62, the tariff-shift rules in paragraph (e) point to the country where the garment was wholly assembled from its components. For made-up articles of headings 63.01 to 63.06, such as blankets, sacks and tarpaulins, the 102.21(e) rule generally gives origin to the country where the fabric was formed, not where it was cut and sewn; certain cotton and wool goods of 63.02 to 63.04 follow a separate dyeing-and-printing rule in paragraph (e)(2). So cutting a jacket’s panels in one country and sewing them in another usually gives the jacket the sewing country’s origin, while cutting and hemming a Chinese-woven tarpaulin in Vietnam does not make it Vietnamese.

Ruling table: assembly operations and outcomes

All of the decisions below come from CBP headquarters. Four were published in the Federal Register as final determinations under 19 CFR Part 177, Subpart B; two are Section 301 rulings; two are earlier rulings as CBP summarized them in those determinations. Each binds only the facts it describes, but together they show where CBP draws the line for assembled products.

The pattern is consistent. Where the country of final assembly also built or programmed the part that does the work, origin moved there. Where final assembly only housed, connected and tested a board made elsewhere, origin stayed with the board. Spoke posts apply this to specific supply chains: moving assembly from China to Vietnam and Mexico nearshoring.

How do advisory rulings and final determinations work?

Subpart B of 19 CFR Part 177 lets a foreign manufacturer, a US importer, a domestic producer of a like product, and certain unions and trade associations ask CBP for an origin decision for government procurement. A final determination applies the law to specific facts, is binding, may be issued before importation, and is published in the Federal Register within 60 days (177.29). A party-at-interest may seek review at the Court of International Trade within 30 days of publication (177.30). An advisory ruling states a general principle and is neither binding nor reviewable.

For marking and Section 301 questions, the route is an ordinary prospective ruling under Subpart A of Part 177, as in HQ H342833 and HQ H344538. A ruling binds CBP only for the transaction it describes (19 CFR 177.9), so a different bill of materials or a process moved between plants needs its own analysis. If the duty at stake is large, ask before you build the plant, and have a customs attorney draft the facts; the description you submit is what the ruling protects.

Which origin test applies? A decision tree

Which origin test applies depends on the question being asked as much as on the product, so start from the question. Work through these yes/no questions in order; one product can need answers to several of them. The tree covers only the rules discussed in this post. It leaves out antidumping and countervailing duty orders, whose own scope language needs a separate review.

1. Are you claiming a lower duty rate under a free trade agreement? If yes, the preference claim follows that agreement’s own rules of origin: for USMCA, General Note 11 to the HTSUS and 19 CFR Part 182 (our USMCA rules of origin guide covers them). Qualifying for preference does not settle marking or Section 301 origin, so continue to question 2 either way.
2. Is the product a textile or apparel product? If yes, 19 CFR 102.21 decides its country of origin for purposes of the customs laws, for goods entered on or after July 1, 1996, except where the question is whether goods are products of Israel (19 CFR 102.22). Skip to question 6. If no, go to question 3.
3. Is the question how to mark a good processed in Canada or Mexico? If yes, the Part 102 rules (the hierarchy in 19 CFR 102.11 and the tariff shifts in 102.20) decide the marking origin, as the last sentence of 19 CFR 134.1(b) requires. Either way, go on to question 4, because the marking answer does not settle Section 301: in HQ H344538 CBP decided the Section 301 origin of a Canadian-made pump by substantial transformation.
4. Is the question marking for goods of any other country, a Section 301 duty, or eligibility for federal procurement under the Trade Agreements Act? If yes, apply substantial transformation: origin is the last country where processing produced a new and different article with a distinct name, character or use (19 CFR 134.1(b); 19 CFR 177.22(a) for procurement). Find the component that gives the product its function, note where it was made and programmed, and compare your bill of materials with the ruling table above. Then go to question 5.
5. Is the product covered by Section 232 metals duties? If yes, those duties apply whatever answer questions 3 and 4 gave (only the rate varies by country), and the entry carries the metal reporting CBP asks for, such as the country where the steel was melted and poured. Go to question 6.
6. Does a published CBP ruling or final determination already cover the same operations: the same functional component made in the same country, and the same steps in the country of final assembly? If yes, record the match and keep the ruling in your origin file, remembering that a ruling binds CBP only for the transaction it describes (19 CFR 177.9). If no, or if the duty at stake is large, ask CBP before you commit: a prospective ruling under Subpart A of 19 CFR Part 177 for marking and Section 301 questions, or a final determination under Subpart B for government procurement.

The tree tells you which test to run, not how it comes out for your product. Deciding where a production step should happen so that origin moves, or whether to restructure a supply chain around a duty, is origin strategy, and that is legal work: have a customs attorney review the facts and draft any ruling request before the plant or the supplier contract is committed.

How do HTS codes support an origin analysis?

HTS codes carry an origin analysis in three places. Part 102 and 102.21 are written entirely as tariff shifts, so for goods of Canada and Mexico and for textiles, origin is a classification exercise on every foreign input. Under substantial transformation, a change of heading between parts and product is supporting evidence at most; none of the rulings in the table turned on it. Even so, classification still counts there, because the description of each part (finished PCBA, bare board, subassembly, unfinished casting) is the vocabulary CBP uses to decide which component gives the product its character. And once origin is fixed, the product’s HTS code decides which Section 301, Section 232 and AD/CVD measures attach.

TariffWolf classifies the finished product and each component to the 6-digit HS level, with the section and chapter notes, GRIs and CBP rulings behind every code, which gives an origin file a documented starting point. Your classifier or broker picks the last four digits of each HTS line, and the origin conclusion itself, where duty or penalties are at stake, belongs with a customs attorney.

Related reading

• Rely on an existing CBP ruling or request your own?
• The forced-labor Section 301 tariff: 9903.05 headings by country, rates and exemptions
• Section 301 China tariffs: lists, rates, exclusions and how to lower the duty
• How to Classify Dual-Use Products

Frequently asked questions

What is the substantial transformation test?

It is the test CBP and the courts use to decide a product’s country of origin when more than one country was involved: origin is the last country where processing turned the inputs into a new and different article with a distinct name, character or use. CBP weighs component origin, the extent of processing and the resulting change case by case.

Does assembling a product in another country change its origin?

Only if the assembly is substantial. Simple assembly of finished components, such as putting a finished circuit board in a case and connecting wires, generally does not change origin. Building or programming the component that gives the product its function, or extensive machining and assembly, often does.

Is there a minimum percentage of value added?

No. CBP’s origin regulations set no value-added threshold for substantial transformation, and the court decisions above do not apply one. Cost can be one fact CBP considers, as in HQ H342833, but it is weighed with the nature of the processing and the components’ roles.

When does CBP use Part 102 instead of substantial transformation?

For marking goods of Canada and Mexico, 19 CFR 134.1(b) applies the Part 102 tariff-shift rules, and 19 CFR 102.21 governs textile and apparel products generally. In HQ H344538, CBP decided Section 301 origin for a Canadian-made pump by substantial transformation, so the two tests can apply to the same product for different purposes.

How do I know which country of origin rule applies to my product?

Start from the purpose. An FTA preference claim follows the agreement’s rules (for USMCA, General Note 11 and 19 CFR Part 182). Textiles and apparel follow 19 CFR 102.21, marking of goods of Canada and Mexico follows the Part 102 tariff-shift rules, and marking for other countries, Section 301 and procurement follow substantial transformation.

If a sourcing change depends on a new country of origin, write down which component gives the product its function, where it is made and programmed, and what happens in the country of final assembly, and compare that with the determinations above before committing. If the answer is not clear from published rulings, a prospective ruling request is cheaper than an origin dispute after the fact.

If you are preparing an origin analysis and need the parts and finished product classified with sources first, book a call with TariffWolf and bring a bill of materials. We will return the 6-digit HS code for each line with the reasoning behind it, and your classifier or broker sets the last four digits. The origin strategy itself, including wherever the decision tree above leads, should be reviewed with your customs attorney.

Sources

• 19 CFR 134.1, definitions (country of origin)
• 19 CFR 102.11, general rules of origin and 19 CFR 102.21, textile and apparel products
• 19 CFR Part 177, including Subpart B on government procurement determinations
• Final determination HQ H331939, 89 FR 54843 (July 2, 2024)
• Final determination HQ H338116 (Federal Register, June 10, 2024)
• Final determination HQ H350894 (Federal Register, January 13, 2026) and HQ H346632 (July 16, 2026)
• CBP ruling HQ H342833 (December 19, 2025) and HQ H344538 (September 11, 2025)