Vietnam Sourcing and the Transshipment Risk Nobody Talks About

In 2017, Vietnam exported approximately $46 billion worth of goods to the United States. By 2024, that number had grown to over $130 billion. The category breakdowns tell the story: the sharpest growth was in electronics, machinery, furniture, and textiles, precisely the categories that faced the steepest Section 301 China tariffs starting in 2018.

CBP noticed. The agency has been running targeted enforcement actions against Vietnam transshipment since 2019, with a significant ramp-up starting in 2023. Several high-profile enforcement actions resulted in retroactive duty bills of 25% on goods that had entered as Vietnam-origin, plus penalties.

If you have moved sourcing to Vietnam since 2018, your origin documentation is under more scrutiny than you may realize.

What Transshipment Actually Means

Transshipment in the CBP context means goods that were produced in Country A, shipped through Country B with minimal processing, and entered into the US as Country B origin to avoid Country A tariffs. The legal term is "false country of origin," and it is treated as fraud, not a tariff classification error.

The key word is "minimal processing." There is no transshipment violation if goods are genuinely manufactured in Vietnam. A Vietnamese factory that takes Chinese steel wire and manufactures it into fasteners, performs significant value-added operations, and can document the manufacturing process is not transshipping.

The violation occurs when:

• Chinese finished goods are physically routed through Vietnam with only relabeling or repackaging
• Vietnamese "manufacturing" consists of final assembly of pre-assembled Chinese sub-components with less than substantial transformation
• Country of origin documentation is falsified or backdated

Substantial transformation is the US standard for origin determination (for most goods). It means the goods must undergo a fundamental change in name, character, or use as a result of the processing in Vietnam. Screwing components together that were pre-assembled in China does not meet this standard.

Why Vietnam's Specific Categories Draw the Most Scrutiny

CBP uses statistical anomaly detection. When import volume in a category grows 3x to 5x in five years, especially from a single country and especially in categories that correlate with Section 301-targeted Chinese products, the agency flags it for enhanced examination.

The highest-risk categories for Vietnam transshipment scrutiny as of early 2026:

• Steel and aluminum products (Chapters 72, 73, 76): Vietnam's domestic steel production capacity did not increase proportionally to its steel product exports to the US.
• Printed circuit boards and electronics assemblies (Chapter 85): Vietnam has genuine electronics manufacturing capacity, but the category also includes many products with minimal Vietnam value-added.
• Furniture and wooden products (Chapter 94): One of the earliest Section 301 enforcement targets. CBP has issued withhold release orders against specific Vietnamese manufacturers.
• Solar panels and related equipment: Active enforcement actions established precedent for how "substantial transformation" applies to solar cell assembly.
• Textiles and apparel (Chapters 61-63): CBP scrutinizes fiber and yarn origin documentation heavily.

How CBP Detects It

CBP's enforcement methodology has evolved. The agency is no longer relying primarily on port examination of physical shipments. Current tools include:

• Statistical gap analysis: If Vietnam's domestic production of a commodity category does not support its export volume to the US, CBP investigates the import-export gap.
• Supply chain audits: For importers flagged for examination, CBP can request full supply chain documentation going back to raw materials, including supplier invoices and factory records.
• CTPAT inquiries: Companies with CTPAT status can lose that status if audits reveal origin documentation deficiencies.
• Third-party tips and competitor reporting: Honest manufacturers who lose business to competitors using false origin documentation have strong incentives to file tips with CBP.
• Entity-level enforcement: CBP and Commerce have issued restrictions on specific Vietnamese manufacturers found to have engaged in transshipment.

What Legitimate Vietnam Sourcing Documentation Looks Like

If your Vietnam sourcing is genuine, the documentation should withstand CBP's worst-case examination. Factory audit trail requirements:

• What raw materials are used and where are they sourced?
• What manufacturing steps occur at the Vietnamese facility?
• What machinery is present and owned by the Vietnamese manufacturer?
• How many direct manufacturing employees?
• What is the production cycle time for the product?

Bill of materials with origin: Every input component should have a country of origin. If a significant portion of the BOM by value is China-origin, you need to demonstrate that the processing in Vietnam constitutes substantial transformation for each input.

Export documentation from China to Vietnam: If your supplier uses Chinese inputs, the import records into Vietnam should be consistent with the production volume. CBP can request these records.

Consistency across time: CBP looks for sudden changes. A Vietnamese supplier that had no US export history in 2017 and suddenly started shipping the exact products that faced Section 301 tariffs in 2018 has an elevated scrutiny profile.

The 3+1 Test for Transshipment Risk Assessment

Before finalizing a Vietnam sourcing relationship, or before your next CBP examination, run this self-assessment:

• Test 1 (Timing): Did this Vietnamese supplier begin or significantly increase production in your specific category after July 2018? If yes, scrutiny is higher.
• Test 2 (Input origin): What percentage of the BOM by value is China-origin? If over 50%, substantial transformation documentation needs to be airtight.
• Test 3 (Value added): What percentage of the final product's value was added in Vietnam? If the Vietnam-added value is less than 35-40%, the substantial transformation argument is weak.
• Test 4 (Factory verification): Have you or a third-party auditor physically visited the manufacturing facility? CBP gives significant weight to importer due diligence.

The Risk Is Not Symmetric

The enforcement risk is not evenly distributed. Small importers under $5M annual import volume from Vietnam are unlikely to receive targeted examination unless they are in a flagged category. Large importers, especially those with sudden category growth, are high-probability examination targets.

The penalty structure matters. Negligent violations under 19 USC 1592 carry penalties of 20% of the domestic value of the merchandise. Grossly negligent violations carry 40%. Fraud carries the full domestic value. For a $10M annual shipment under a false origin claim, the fraud penalty exposure is $10M, not just the duties avoided.

Retroactive liability extends back four years under the statute of limitations for fraudulent entries. A transshipment relationship that has been running since 2019 could carry seven years of retroactive duty exposure plus penalties.

Using Transshipment Risk Scoring Before You Commit

Triangle Trade Intelligence includes a transshipment-risk endpoint that scores country-of-origin risk for a given HTS code and supplier country combination. The score is based on:

• Historical CBP enforcement patterns for the HS category
• Category-level import growth anomalies by country
• Active withhold release orders and enforcement actions
• Known high-risk entity indicators

For a new Vietnam supplier relationship, running the HTS code through the transshipment-risk endpoint gives you an objective risk score before you are committed. If the score is elevated, you know to demand more rigorous factory documentation before signing the contract, not after CBP's first examination.

The endpoint is available through the API at the Starter tier and above. Results include the policy source and Federal Register citations underlying the risk assessment, so your compliance team has documentation to file.

The Bottom Line

Vietnam is a legitimate manufacturing hub. Many Vietnam-origin imports are exactly what they say they are: goods manufactured in Vietnam by Vietnamese and foreign-invested factories with documented supply chains. Those importers have nothing to worry about beyond normal documentation discipline.

But the 2018-2022 rush to reclassify Chinese goods as Vietnam-origin left a significant enforcement backlog. CBP is working through it systematically. If your Vietnam sourcing started or scaled significantly after the first Section 301 tariffs, and you have not done a rigorous documentation audit, now is the time to do it, on your terms rather than CBP's.