1.1 The Changing Landscape of Global Trade

International trade has undergone profound transformation over the past decade. Global supply chains, once designed primarily to maximize efficiency and minimize production costs, are increasingly shaped by geopolitical developments, economic security concerns, trade sanctions, and evolving customs enforcement policies. As multinational enterprises diversify manufacturing operations and relocate production facilities across multiple jurisdictions, determining the true country of origin of goods has become significantly more complex than ever before.

The growing interdependence of international production has resulted in a single product being designed in one country, manufactured using components sourced from several jurisdictions, assembled in another country, and ultimately exported to consumers worldwide. While globalization has substantially increased economic efficiency, it has also created new opportunities for businesses to restructure supply chains in ways that may obscure the actual origin of products.

In response to these developments, customs authorities around the world have intensified their scrutiny of origin declarations, particularly where products are exported through third countries before entering their final destination. Consequently, the legal determination of a product’s origin has become a matter of increasing commercial and regulatory significance.

1.2 The Importance of Rules of Origin

Rules of Origin (“ROO”) constitute one of the fundamental pillars of international trade law. They determine the economic nationality of goods and establish whether products qualify for preferential tariff treatment under Free Trade Agreements (“FTAs”), regional trade agreements, or other trade preference schemes.

Beyond preferential tariff treatment, Rules of Origin also serve a broader regulatory function. They enable governments to administer anti-dumping duties, countervailing duties, safeguard measures, quantitative restrictions, sanctions, origin marking requirements, public procurement rules, and national security measures. In other words, the determination of origin affects not only customs duties but also a wide range of legal rights and obligations applicable to international trade.

Contrary to common commercial perception, the country from which goods are exported is not necessarily the country in which those goods legally originate. Likewise, the issuance of a Certificate of Origin (“C/O”) does not automatically establish the origin of the goods for all legal purposes. Customs authorities of the importing country retain the authority to independently verify the actual origin of the products based on applicable Rules of Origin and supporting evidence.

Accordingly, businesses involved in international manufacturing, sourcing, logistics, and export activities must understand that origin determination is ultimately a legal assessment based upon production processes rather than merely documentary formalities.

1.3 The U.S.–China Trade Conflict and Heightened Origin Scrutiny

The importance of Rules of Origin has become particularly evident following the escalation of trade tensions between the United States and the People’s Republic of China.

Beginning in 2018, the Office of the United States Trade Representative (“USTR”) imposed additional tariffs on a broad range of Chinese-origin products pursuant to Section 301 of the Trade Act of 1974, following investigations into certain Chinese trade practices considered unfair by the United States. These additional tariffs substantially increased the cost of importing numerous Chinese products into the U.S. market and fundamentally altered global sourcing strategies.

In response, many multinational companies diversified manufacturing operations outside China under what has become widely known as the “China Plus One” strategy. While many businesses legitimately established new production facilities in countries such as Thailand, Vietnam, Malaysia, Indonesia, and Mexico, concerns also emerged regarding the possibility that certain exporters might merely route Chinese-origin products through third countries without undertaking sufficient manufacturing activities capable of conferring a new origin.

Such practices, commonly referred to as trade circumvention, transshipment, or the misuse of origin declarations, have become a significant enforcement priority for customs authorities worldwide.

1.4 Thailand’s Growing Role in Regional Supply Chains

Thailand has emerged as one of Southeast Asia’s principal manufacturing and export hubs. Its strategic geographic location, well-developed industrial infrastructure, extensive network of Free Trade Agreements, and diversified manufacturing base have attracted substantial foreign direct investment across industries including electronics, automotive, machinery, electrical appliances, chemicals, food processing, medical devices, and renewable energy.

At the same time, Thailand’s expanding role in global supply chains has also resulted in increased regulatory attention concerning the issuance of Certificates of Origin. As products manufactured using imported components continue to increase in complexity, exporters must carefully assess whether manufacturing operations performed in Thailand satisfy the applicable Rules of Origin before applying for a Thai Certificate of Origin.

Failure to conduct an appropriate origin assessment may expose exporters, importers, manufacturers, and supply chain participants to significant customs liabilities, contractual disputes, regulatory investigations, and reputational damage.

1.5 Misconceptions Regarding Certificates of Origin

One of the most common misconceptions in international trade is the assumption that once a Certificate of Origin has been validly issued by the competent authority of the exporting country, the importing country is legally bound to accept the declared origin.

In reality, a Certificate of Origin is generally regarded as supporting evidence rather than conclusive proof of origin. Customs authorities retain the right to examine whether the underlying production processes genuinely satisfy the applicable origin criteria. If the competent authority of the importing country concludes that the goods fail to meet the relevant Rules of Origin, it may reject the declared origin notwithstanding the existence of a duly issued Certificate of Origin.

Accordingly, businesses should view the Certificate of Origin not as a guarantee of customs treatment, but rather as one component of a broader evidentiary framework that must be supported by complete production records, supplier documentation, bills of materials, manufacturing processes, cost calculations, and other objective evidence demonstrating compliance with the applicable Rules of Origin.

1.6 Purpose and Scope of This Paper

This paper examines the legal framework governing Certificates of Origin and Rules of Origin in the context of modern international trade, with particular emphasis on the growing enforcement challenges arising from global supply chain restructuring.

It further analyses the legal implications of Minimal Operations, Substantial Transformation, and the distinction between the country of export and the country of origin. Particular attention is given to the impact of Section 301 of the U.S. Trade Act of 1974, the increasing scrutiny exercised by U.S. Customs and Border Protection (“CBP”), and the legal risks associated with the misuse of Certificates of Origin.

Finally, this paper considers Thailand’s role within regional manufacturing networks and provides a practical case study involving the movement of goods between China, Thailand, and the United States. It concludes by offering practical compliance recommendations aimed at assisting manufacturers, exporters, importers, and legal practitioners in navigating the increasingly complex landscape of international origin compliance.

The central proposition of this paper is straightforward: a Certificate of Origin is not a passport for goods. Rather, it is documentary evidence whose legal value depends entirely upon whether the underlying facts satisfy the applicable Rules of Origin.

Understanding Certificates of Origin (C/O)

2.1 Introduction

The Certificate of Origin (“C/O”) is one of the most important documents used in international trade. Although frequently regarded as a routine shipping document, its legal significance extends far beyond customs clearance. A Certificate of Origin serves as documentary evidence regarding the country in which goods are considered to originate under the applicable Rules of Origin. This determination directly affects the customs treatment of imported goods, including eligibility for preferential tariff rates, the application of trade remedies, compliance with import restrictions, and various regulatory requirements imposed by the importing country.

Despite its widespread use, the legal nature of a Certificate of Origin is often misunderstood. Many exporters assume that once a C/O has been issued by the competent authority of the exporting country, the declared origin becomes legally conclusive. This assumption is incorrect. Under international customs practice, a Certificate of Origin is generally regarded as evidence of origin rather than irrefutable proof. Customs authorities in the importing country retain the legal authority to verify the accuracy of the declared origin and to reject the Certificate if the goods fail to satisfy the applicable Rules of Origin.

Understanding the legal function and limitations of a Certificate of Origin is therefore essential for manufacturers, exporters, importers, customs brokers, and legal practitioners involved in cross-border trade.

2.2 Definition of a Certificate of Origin

A Certificate of Origin is a document certifying that goods exported from a particular country satisfy the applicable Rules of Origin and are considered to originate in that country for the purposes specified under the relevant international agreement or domestic customs legislation.

Depending on the applicable legal framework, the Certificate may be issued by a governmental authority, a designated issuing agency, or, under certain Free Trade Agreements, completed by the exporter through a self-certification system.

It is important to distinguish between the issuance of the Certificate and the legal determination of origin. The Certificate merely reflects the information and supporting evidence presented by the exporter at the time of application. It does not prevent the importing customs authority from conducting an independent review of the origin of the goods.

2.3 Legal Functions of a Certificate of Origin

A Certificate of Origin performs several important legal and commercial functions.

First, it enables importers to claim preferential tariff treatment under applicable Free Trade Agreements (“FTAs”), provided that the goods satisfy the relevant Rules of Origin.

Second, it assists customs authorities in determining whether anti-dumping duties, countervailing duties, safeguard measures, quotas, or other trade remedies should apply.

Third, it provides evidence for compliance with import licensing requirements, product marking regulations, government procurement rules, and other country-specific regulatory obligations.

Finally, the Certificate serves as an important commercial document supporting customs declarations, letters of credit, and contractual obligations between buyers and sellers.

Although these functions are significant, none of them transforms the Certificate into conclusive legal proof of origin. The legal status of the goods ultimately depends upon whether the underlying production process satisfies the applicable origin criteria.

2.4 Types of Certificates of Origin

Certificates of Origin are generally classified into two principal categories: Non-Preferential Certificates of Origin and Preferential Certificates of Origin.

(a) Non-Preferential Certificates of Origin

A Non-Preferential Certificate of Origin certifies the country of origin for purposes unrelated to tariff preferences. Such Certificates are commonly required to comply with import regulations, trade statistics, sanctions, government procurement requirements, or country-of-origin marking obligations.

The issuance of a Non-Preferential C/O does not entitle the importer to reduced customs duties. Instead, it serves as evidence of origin where no preferential trade arrangement applies.

(b) Preferential Certificates of Origin

A Preferential Certificate of Origin is issued pursuant to a Free Trade Agreement or other preferential trade arrangement. It enables qualified goods to benefit from reduced or zero customs duties, provided that all applicable Rules of Origin have been satisfied.

Examples include Certificates issued under the ASEAN Trade in Goods Agreement (ATIGA), the Regional Comprehensive Economic Partnership (RCEP), the ASEAN–China Free Trade Agreement, and numerous bilateral Free Trade Agreements concluded by Thailand.

Because preferential tariff treatment results in significant financial benefits, customs authorities generally apply a higher level of scrutiny when examining Preferential Certificates of Origin.

2.5 Issuance of Certificates of Origin in Thailand

In Thailand, Certificates of Origin are generally issued by the Department of Foreign Trade under the Ministry of Commerce or other authorised issuing bodies, depending upon the applicable trade agreement.

Before issuing the Certificate, the issuing authority normally examines supporting documentation submitted by the exporter, including production records, bills of materials, supplier declarations, manufacturing information, invoices, and other evidence intended to demonstrate compliance with the applicable Rules of Origin.

However, the issuing authority ordinarily relies upon the information provided by the applicant. Consequently, the issuance of a Certificate should not be interpreted as an official determination that the importing country is legally bound to accept the declared origin.

2.6 Certificate of Origin Does Not Determine Origin Conclusively

One of the most important legal principles governing international trade is that the issuance of a Certificate of Origin does not conclusively determine the origin of the goods.

Importing customs authorities possess independent authority to verify whether the declared origin is consistent with the applicable Rules of Origin. Such verification may involve requests for additional documentation, factory inspections, supplier verification, production record reviews, or retrospective investigations.

Where the customs authority concludes that the goods fail to satisfy the applicable origin requirements, it may reject the Certificate of Origin notwithstanding the fact that it was properly issued by the exporting country.

Accordingly, exporters should regard the Certificate as supporting evidence rather than a legal guarantee.

2.7 Common Misconceptions

Several misconceptions frequently arise in commercial practice.

The first is the belief that the country from which goods are shipped automatically becomes the country of origin. This is incorrect. Exportation through a particular country does not, by itself, confer origin.

The second misconception is that repackaging, relabelling, or simple assembly automatically changes the origin of goods. In most cases, such activities constitute minimal operations that are insufficient to establish a new origin.

A third misconception is that possession of a Certificate of Origin prevents customs authorities from conducting further investigation. In reality, customs authorities may verify origin both before and after importation and may reject a Certificate where supporting evidence is inadequate.

Finally, some businesses assume that origin is determined solely by the location of the final assembly operation. Modern Rules of Origin are considerably more sophisticated and frequently require an assessment of tariff classification changes, regional value content, specific manufacturing processes, or substantial transformation.

2.8 Practical Importance for Businesses

For manufacturers and exporters, obtaining a Certificate of Origin should represent the final step in an origin compliance process rather than its starting point.

Before applying for a Certificate, businesses should carefully evaluate the sourcing of raw materials, manufacturing activities, production costs, tariff classifications, and documentary evidence to ensure that the applicable Rules of Origin have genuinely been satisfied.

Maintaining comprehensive records is equally important. Production records, supplier declarations, bills of materials, cost calculations, inventory records, customs declarations, and manufacturing flowcharts may all become critical evidence during an origin verification conducted by the importing customs authority.

An effective origin compliance programme therefore requires not only accurate documentation but also a thorough understanding of the legal principles governing origin determination.

Rules of Origin: The Legal Framework for Determining the Nationality of Goods

3.1 Introduction

In international trade, one of the most fundamental legal questions is deceptively simple: Where do goods actually originate? Although the answer may appear obvious, determining the country of origin is often one of the most technically complex aspects of customs law. Modern products are rarely manufactured entirely within a single jurisdiction. Instead, they are commonly produced through sophisticated global supply chains involving multiple countries, each contributing raw materials, intermediate components, manufacturing processes, assembly operations, testing, packaging, and distribution.

Consequently, the legal origin of a product cannot be determined merely by identifying the country from which it was exported or the location where the final shipment commenced. Rather, origin is determined by applying a specific set of legal criteria collectively known as the Rules of Origin (“ROO”).

Rules of Origin provide the legal framework for determining the economic nationality of goods. They establish whether a product is considered to originate in a particular country for customs purposes and, consequently, whether the product qualifies for preferential tariff treatment, is subject to trade remedies, or must comply with country-specific import restrictions.

Without internationally recognised Rules of Origin, the administration of modern customs law would become inconsistent and susceptible to manipulation. They therefore serve as an essential mechanism for ensuring fairness, transparency, and predictability in international trade.

3.2 The Purpose of Rules of Origin

The primary purpose of Rules of Origin is to identify the country with which goods have the closest economic connection. Contrary to popular belief, Rules of Origin are not designed solely to determine eligibility for preferential tariff treatment. They perform a much broader regulatory function within the international trading system.

Origin determination affects numerous legal consequences, including:

• Eligibility for preferential tariff treatment under Free Trade Agreements (FTAs);
• Application of anti-dumping and countervailing duties;
• Safeguard measures;
• Quantitative restrictions and import quotas;
• Country-of-origin marking requirements;
• Public procurement rules;
• Economic sanctions and export control measures; and
• Trade statistics and customs administration.

Accordingly, determining the origin of goods is not merely an administrative exercise but a legal determination capable of significantly affecting the commercial viability of international transactions.

3.3 Preferential and Non-Preferential Rules of Origin

Rules of Origin are generally divided into two principal categories: Preferential Rules of Origin and Non-Preferential Rules of Origin.

Preferential Rules of Origin apply under Free Trade Agreements and other preferential trading arrangements. Their purpose is to determine whether imported goods qualify for reduced or zero customs duties. Because preferential treatment represents a significant economic benefit, these rules are often detailed and product-specific.

By contrast, Non-Preferential Rules of Origin apply where no preferential trade arrangement exists. They are primarily used to administer customs tariffs, trade remedies, import restrictions, origin marking requirements, government procurement, and statistical reporting.

Although both categories seek to identify the country of origin, their legal consequences and technical requirements may differ substantially.

3.4 Fundamental Principles of Origin Determination

International Rules of Origin generally recognise two principal methods for determining origin.

(a) Wholly Obtained Goods

The first method applies where goods are entirely obtained or produced within a single country without incorporating foreign materials.

Examples include:

• Minerals extracted from the territory of a country;
• Agricultural products harvested within that country;
• Live animals born and raised there;
• Fish caught by qualifying vessels;
• Products obtained exclusively from wholly obtained materials.

Because no foreign materials are involved, determining origin is relatively straightforward.

(b) Substantial Transformation

The second and considerably more complex method applies where goods are manufactured using materials originating from multiple countries.

Under this principle, origin is attributed to the country in which the imported materials undergo a substantial transformation, resulting in the creation of a new and commercially distinct product.

Although the precise definition varies among different trade agreements, substantial transformation generally requires manufacturing operations that fundamentally alter the nature, characteristics, functionality, or commercial identity of the product.

Simple processing operations are ordinarily insufficient.

3.5 Principal Tests for Determining Substantial Transformation

Modern Rules of Origin employ several recognised methodologies to determine whether substantial transformation has occurred.

(a) Change in Tariff Classification (CTC)

One of the most widely adopted methods is the Change in Tariff Classification test.

This approach examines whether the manufacturing process changes the customs classification of the product under the Harmonized System (“HS”).

The degree of required change may vary depending upon the applicable agreement and product.

Common examples include:

• Change in Chapter (CC);
• Change in Tariff Heading (CTH);
• Change in Tariff Subheading (CTSH).

Where the required tariff shift has occurred, origin may be conferred, subject to any additional requirements.

(b) Regional Value Content (RVC)

Certain agreements determine origin by reference to the proportion of value added within the exporting country or region.

Regional Value Content calculations typically compare the value of originating materials and manufacturing costs against the final value of the exported product.

Different FTAs prescribe different minimum thresholds, often ranging between 35% and 45%.

This method seeks to ensure that meaningful economic activity has occurred within the exporting country.

(c) Specific Processing Rules

Certain industries require designated manufacturing operations to be completed before origin may be conferred.

These rules are particularly common in industries such as:

• Chemicals;
• Textiles;
• Steel;
• Pharmaceuticals;
• Automotive products;
• Electronics.

Where the specified processing operation has not occurred, origin cannot be obtained even if other criteria have been satisfied.

3.6 Minimal Operations: When Origin Does Not Change

Not every manufacturing activity is sufficient to establish a new country of origin.

Most international agreements expressly identify certain operations that are regarded as minimal, simple, or insufficient processing.

Examples commonly include:

• Repacking;
• Relabelling;
• Sorting;
• Cleaning;
• Washing;
• Ironing;
• Simple cutting;
• Simple assembly;
• Dilution;
• Packaging for retail sale;
• Affixing trademarks or barcodes.

These activities generally preserve the essential identity of the goods and therefore do not amount to substantial transformation.

The distinction between substantial manufacturing and minimal operations is one of the most significant issues in modern origin disputes and will be examined in greater detail in Chapter 4.

3.7 Documentary Evidence Supporting Origin

Compliance with Rules of Origin extends beyond the manufacturing process itself. Exporters must also maintain sufficient documentary evidence demonstrating that the applicable origin requirements have been satisfied.

Typical supporting documents include:

• Bills of Materials (BOM);
• Supplier declarations;
• Production flowcharts;
• Manufacturing records;
• Cost calculations;
• Purchase invoices;
• Import declarations;
• Inventory records;
• Production schedules;
• Quality control records.

Failure to maintain adequate documentation may result in the rejection of an otherwise valid origin claim.

3.8 Origin Verification

The importing customs authority is not bound to accept an origin declaration solely because a Certificate of Origin has been issued.

Customs authorities may conduct origin verification through:

• Requests for additional information;
• Review of production records;
• Verification of supplier declarations;
• Factory inspections;
• Interviews with manufacturers;
• Cross-border customs cooperation;
• Retroactive investigations.

Where the available evidence does not support the declared origin, the customs authority may deny preferential treatment, recover unpaid duties, and impose penalties in accordance with the applicable legislation.

3.9 The Importance of Rules of Origin in Global Supply Chains

The increasing fragmentation of global manufacturing has significantly increased the importance of Rules of Origin.

Modern products frequently incorporate components originating from numerous jurisdictions before final assembly takes place in another country. Consequently, determining origin requires careful legal analysis rather than reliance upon assumptions regarding the place of shipment or final assembly.

The restructuring of global supply chains following the U.S.–China trade tensions has further intensified customs scrutiny of origin declarations. Customs authorities now examine not only where products were shipped but also where value was created, how manufacturing occurred, and whether the operations performed were sufficient to confer origin under the applicable legal framework.

Minimal Operations: Why Certain Manufacturing Activities Do Not Confer Origin

4.1 Introduction

One of the most frequently misunderstood concepts in international trade law is the distinction between substantial transformation and minimal operations. Many businesses assume that any activity performed within a country is sufficient to establish that country as the origin of the goods. In practice, however, international Rules of Origin adopt a far more rigorous approach.

Modern manufacturing frequently involves production processes taking place across several jurisdictions. Raw materials may be extracted in one country, processed into intermediate components in another, assembled elsewhere, and ultimately exported from a different country. Consequently, the mere fact that certain operations are carried out within a particular country does not automatically confer origin upon the finished product.

To preserve the integrity of international trade, most Free Trade Agreements (“FTAs”), customs legislation, and international origin rules expressly distinguish between manufacturing operations that genuinely create new economic value and those regarded as merely preparatory, logistical, or cosmetic. The latter are commonly referred to as Minimal Operations, Insufficient Working or Processing, or Simple Operations.

These concepts play a critical role in preventing the misuse of Certificates of Origin and the circumvention of customs duties through superficial processing conducted in intermediate countries.

4.2 The Legal Rationale Behind Minimal Operations

The concept of Minimal Operations is founded upon a simple legal principle: origin should reflect genuine economic production rather than artificial commercial arrangements.

If origin could be obtained merely by changing packaging, affixing a new label, or routing goods through another country, the effectiveness of Rules of Origin would be seriously undermined. Exporters could easily avoid customs duties, anti-dumping measures, safeguard actions, or sanctions by carrying out insignificant processing in a third country while the essential character of the goods remained unchanged.

Accordingly, international origin rules require that manufacturing activities involve meaningful economic transformation before a new country of origin may be recognised.

This principle is reflected in numerous international trade agreements, including the WTO Agreement on Rules of Origin, the Revised Kyoto Convention, the Regional Comprehensive Economic Partnership (RCEP), and many bilateral and regional Free Trade Agreements.

4.3 Characteristics of Minimal Operations

Although the precise wording varies among different legal instruments, Minimal Operations generally possess several common characteristics.

First, they do not substantially alter the physical characteristics or essential identity of the goods.

Second, they do not create a new commercial product recognised in international trade.

Third, they involve relatively simple procedures requiring limited technical expertise or industrial capability.

Finally, the value added by such operations is generally insignificant when compared with the overall value of the finished goods.

Accordingly, these activities are regarded as commercially useful but legally insufficient to confer origin.

4.4 Common Examples of Minimal Operations

International trade agreements commonly identify the following activities as examples of insufficient processing.

(a) Repacking and Repackaging

Goods imported in bulk may be divided into smaller retail packages, transferred into new containers, or prepared for consumer sale. Although these activities improve marketability, they do not alter the nature or identity of the goods.

For example, coffee beans produced in Country A and repacked into smaller bags in Thailand remain products of Country A unless further qualifying manufacturing occurs.

(b) Relabelling and Rebranding

Replacing labels, trademarks, logos, serial numbers, instruction manuals, or packaging artwork likewise does not create a new origin.

The commercial identity of the seller may change, but the legal origin of the goods remains unaffected.

(c) Cleaning, Washing, or Polishing

Cleaning products, removing dust, washing agricultural products, polishing metal products, or applying protective coatings intended solely to preserve appearance or facilitate transportation are generally regarded as insufficient processing.

(d) Sorting, Grading, and Classification

Separating products according to quality, colour, weight, dimensions, or specifications does not fundamentally alter the goods themselves.

For example, sorting imported gemstones or agricultural products into premium and standard grades does not confer a new country of origin.

(e) Simple Packaging for Retail Sale

Placing imported products into retail packaging, adding promotional materials, attaching barcodes, or assembling consumer gift sets ordinarily constitutes minimal processing.

The goods remain legally attributable to the country in which they were originally manufactured.

(f) Simple Assembly

One of the most controversial categories concerns simple assembly.

The assembly of pre-manufactured imported components using basic fastening techniques—such as screwing, clipping, gluing, or bolting—may be insufficient where the process does not require significant manufacturing expertise or materially transform the product.

Whether assembly is regarded as “simple” depends upon the complexity of the production process, the technological contribution made, and the applicable product-specific Rules of Origin.

4.5 Minimal Operations and Substantial Transformation

The distinction between Minimal Operations and Substantial Transformation is one of degree rather than terminology.

Substantial Transformation requires manufacturing operations that fundamentally alter the identity, character, or use of the imported materials. By contrast, Minimal Operations merely prepare, preserve, package, or market goods without changing their essential commercial identity.

The following comparison illustrates the distinction:

Minimal Operations	Substantial Transformation
Repacking	Manufacturing a new product
Relabelling	Chemical conversion
Cleaning	Complex machining
Sorting	Industrial fabrication
Simple packaging	Product-specific manufacturing
Simple assembly	Significant value-added production

This distinction is central to determining whether a new origin has been established.

4.6 Minimal Operations in the Context of Global Supply Chains

The increasing fragmentation of manufacturing has significantly increased the importance of Minimal Operations.

Many multinational companies now distribute production across multiple countries. Components manufactured in one jurisdiction may be shipped elsewhere for assembly, testing, inspection, packaging, or distribution before final export.

While such arrangements are commercially legitimate, they also create opportunities for origin manipulation where businesses attempt to attribute origin to countries performing only insignificant processing.

Consequently, customs authorities increasingly examine the actual manufacturing activities performed in each jurisdiction rather than relying solely upon shipping documentation or Certificates of Origin.

4.7 Thailand as an Intermediate Manufacturing Hub

Thailand occupies a strategic position within Asian manufacturing networks. Numerous imported products undergo certain operations in Thailand before being exported worldwide.

Examples include:

• Repackaging imported consumer products for ASEAN markets;
• Relabelling electrical appliances for local distributors;
• Assembling imported components into retail kits;
• Packaging automotive spare parts;
• Preparing medical devices for shipment.

These activities may serve important commercial purposes. Nevertheless, unless the applicable Rules of Origin are satisfied, such operations alone are generally insufficient to establish Thai origin.

Businesses should therefore carefully distinguish between operations undertaken for commercial convenience and manufacturing activities capable of conferring origin.

4.8 Implications for Certificate of Origin Applications

The distinction between substantial manufacturing and Minimal Operations has significant implications for exporters seeking a Certificate of Origin.

Before submitting an application, exporters should assess whether the production undertaken genuinely satisfies the applicable Rules of Origin rather than assuming that any activity performed within Thailand is sufficient.

Applications based solely upon repackaging, relabelling, simple assembly, or other minimal processing may expose businesses to customs investigations, retroactive duty assessments, rejection of preferential treatment, contractual disputes, and reputational harm.

A prudent exporter should therefore undertake a comprehensive origin assessment supported by production records, supplier documentation, bills of materials, tariff classifications, and value-content calculations before certifying origin.

Section 301 of the U.S. Trade Act of 1974: Trade Enforcement, Supply Chain Restructuring, and the Growing Importance of Rules of Origin

5.1 Introduction

The determination of the country of origin has always been an essential component of customs law. However, its importance has increased dramatically following the escalation of trade tensions between the United States and the People’s Republic of China. Since 2018, the implementation of additional tariffs under Section 301 of the U.S. Trade Act of 1974 has fundamentally reshaped global supply chains and transformed customs enforcement practices worldwide.

Prior to the imposition of Section 301 tariffs, origin determination was primarily associated with preferential tariff treatment under Free Trade Agreements (“FTAs”), anti-dumping measures, and customs administration. Today, however, origin has become a strategic issue affecting corporate supply chain decisions, manufacturing investment, and international trade compliance.

As companies seek to reduce tariff exposure by relocating production outside China, customs authorities have become increasingly vigilant in examining whether manufacturing activities undertaken in third countries genuinely create a new country of origin or merely constitute attempts to circumvent U.S. trade measures.

This chapter examines the legal framework of Section 301, its impact on global commerce, and the reasons why Rules of Origin have become one of the most heavily scrutinised aspects of modern international trade.

5.2 Legislative Background of Section 301

Section 301 forms part of the Trade Act of 1974, a comprehensive statute enacted by the United States Congress to strengthen the country’s ability to respond to unfair foreign trade practices.

The legislation authorises the Office of the United States Trade Representative (“USTR”) to investigate whether acts, policies, or practices adopted by foreign governments are unreasonable, discriminatory, or inconsistent with international trade obligations and whether such practices burden or restrict U.S. commerce.

Where the USTR determines that such practices exist, the United States may adopt appropriate trade measures, including the suspension of trade concessions, the imposition of additional customs duties, import restrictions, or other retaliatory actions designed to encourage the elimination of the offending practices.

Unlike ordinary customs legislation, Section 301 is not intended to regulate import procedures. Rather, it functions as a trade policy instrument that permits the United States to respond to systemic trade practices considered harmful to U.S. economic interests.

5.3 The Section 301 Investigation Against China

In August 2017, the USTR initiated an investigation into certain acts, policies, and practices of China concerning technology transfer, intellectual property, and innovation.

The investigation concluded that several Chinese practices were considered unreasonable or discriminatory and were alleged to place an unfair burden on U.S. commerce. The resulting report formed the basis for a series of trade actions beginning in 2018, including the imposition of additional tariffs on a broad range of Chinese-origin products.

Rather than targeting individual exporters, the measures applied generally to products determined to originate in China and classified under specified tariff schedules.

Consequently, the legal determination of origin became a decisive factor in establishing whether imported goods were subject to the additional tariffs.

5.4 Section 301 Tariffs and Their Commercial Impact

The additional tariffs imposed under Section 301 affected thousands of product categories across numerous industries, including electronics, machinery, automotive components, industrial equipment, furniture, chemicals, consumer goods, and electrical appliances.

For many importers, the tariffs substantially increased landed costs and reduced commercial competitiveness within the U.S. market.

Businesses therefore began exploring alternative sourcing strategies, including:

• relocating manufacturing facilities outside China;
• diversifying suppliers across multiple jurisdictions;
• increasing regional manufacturing capacity;
• restructuring production processes; and
• redesigning international supply chains.

This transformation became widely known as the China Plus One Strategy, under which multinational enterprises expanded manufacturing activities into countries including Thailand, Vietnam, Malaysia, Indonesia, India, and Mexico.

Many of these investments represented genuine industrial expansion supported by substantial manufacturing operations. However, customs authorities also recognised that some businesses might attempt to minimise tariff exposure through artificial restructuring that failed to satisfy the applicable Rules of Origin.

5.5 Section 301 and the Growing Importance of Rules of Origin

One of the most significant consequences of Section 301 has been the renewed importance of Rules of Origin.

Because the additional duties apply to Chinese-origin goods, the legal determination of origin directly determines whether the tariffs apply.

This distinction is critical. A product manufactured in China does not cease to be Chinese in origin merely because it is exported through another country or undergoes limited processing before shipment to the United States.

Similarly, a Certificate of Origin issued by an intermediate country does not automatically establish that the product has acquired a new legal origin.

Instead, customs authorities examine whether the manufacturing activities undertaken outside China satisfy the applicable Rules of Origin, including the requirements relating to substantial transformation, tariff classification changes, regional value content, or product-specific processing rules.

Where those requirements are not met, the product may continue to be regarded as Chinese-origin goods despite subsequent processing elsewhere.

5.6 Legitimate Supply Chain Diversification Versus Trade Circumvention

It is important to distinguish between legitimate business restructuring and unlawful trade circumvention.

Many multinational enterprises have invested heavily in establishing manufacturing operations outside China. These investments frequently involve new factories, advanced production equipment, skilled labour, technology transfer, local sourcing, and comprehensive manufacturing processes capable of satisfying the applicable Rules of Origin.

In such circumstances, products manufactured in the new facilities may legitimately acquire a new country of origin.

By contrast, customs authorities have expressed concern regarding situations in which products manufactured almost entirely in China are merely routed through another jurisdiction before export to the United States.

Examples include:

• replacing packaging;
• affixing new labels;
• changing exporters;
• issuing new commercial invoices;
• conducting simple assembly;
• consolidating shipments; or
• storing goods in warehouses pending re-export.

Where such activities do not constitute substantial transformation, they generally do not confer a new country of origin.

5.7 Why Certificates of Origin Receive Increased Scrutiny

The implementation of Section 301 has significantly increased customs scrutiny of Certificates of Origin.

Historically, customs authorities often accepted Certificates of Origin unless specific concerns arose regarding their authenticity. Today, however, the existence of a Certificate is frequently regarded as the starting point rather than the conclusion of origin verification.

Importing authorities may request extensive supporting documentation, including:

• production records;
• supplier declarations;
• bills of materials;
• manufacturing flowcharts;
• cost calculations;
• factory production schedules;
• machinery lists;
• inventory records;
• purchase invoices; and
• import documentation for raw materials.

The objective is not merely to verify the authenticity of the Certificate itself but to determine whether the underlying manufacturing activities genuinely satisfy the applicable Rules of Origin.

5.8 Implications for Thai Exporters

Thailand has become an increasingly attractive destination for foreign investment following the restructuring of global supply chains.

Many companies have established genuine manufacturing operations within Thailand, contributing significantly to industrial development and export growth.

At the same time, Thai exporters should recognise that the existence of manufacturing facilities within Thailand does not automatically establish Thai origin for every exported product.

Where production activities consist primarily of repackaging, relabelling, sorting, or other minimal operations, the resulting products may fail to satisfy the applicable Rules of Origin.

Accordingly, exporters seeking to obtain Thai Certificates of Origin should conduct comprehensive origin assessments before certifying that their products qualify as Thai-origin goods.

Failure to do so may expose both exporters and overseas importers to customs investigations, denial of preferential treatment, retroactive duties, financial penalties, contractual disputes, and reputational harm.

5.9 Compliance Considerations for Businesses

The introduction of Section 301 has fundamentally changed the approach businesses must adopt toward origin compliance.

Origin should no longer be viewed solely as a customs documentation requirement. Instead, it should form part of a broader corporate compliance framework encompassing procurement, manufacturing, logistics, customs, taxation, and legal risk management.

Businesses should establish internal procedures to:

• evaluate Rules of Origin before production begins;
• review tariff classification and value-content calculations;
• maintain comprehensive production records;
• monitor supplier declarations;
• conduct periodic internal origin audits;
• obtain legal advice where origin is uncertain; and
• ensure consistency between commercial documentation and actual manufacturing activities.

These measures not only reduce customs risk but also strengthen the credibility of exporters in international markets.

5.10 Conclusion

Section 301 of the U.S. Trade Act of 1974 has transformed the global trading environment by placing the legal determination of origin at the centre of customs enforcement.

The additional tariffs imposed on Chinese-origin products have encouraged legitimate supply chain diversification while simultaneously increasing regulatory scrutiny of transactions involving intermediate manufacturing jurisdictions.

As a consequence, the distinction between substantial transformation and minimal operations has become more important than ever. Businesses can no longer assume that routing goods through another country or obtaining a Certificate of Origin will automatically alter the legal origin of their products.

Instead, origin must be supported by genuine manufacturing activities that satisfy the applicable Rules of Origin. A Certificate of Origin remains an important documentary instrument, but its legal value ultimately depends upon the underlying facts.

The following chapter builds upon these principles by examining a practical case study involving the movement of goods from China to Thailand and subsequently to the United States, illustrating how origin determinations are assessed in practice and the legal consequences that may arise where the applicable Rules of Origin are not satisfied.