Turkish customs found underpaid import duties during an inspection or post-clearance audit? Learn how additional assessments and penalties work, when importers can challenge the calculation, the 15-day objection period, customs settlement options, and the risks for foreign companies in Turkey.

A customs inspection in Turkey can uncover an underpayment long after goods have entered the country. The discrepancy may arise from an incorrect tariff classification, understated customs value, incorrect country of origin, an improperly claimed exemption, an omitted royalty or license fee, an incorrect import VAT calculation, or another customs declaration issue.

For a foreign importer, the discovery of underpaid duties does not necessarily mean that customs will simply request payment of the difference. Depending on the legal basis and circumstances, the authorities may issue an additional customs duty assessment together with an administrative monetary penalty. In more serious cases involving allegations of intentional misconduct, separate implications under anti-smuggling legislation may also need to be examined.

This is particularly important in 2026 because retrospective customs enforcement has intensified significantly. On July 7, 2026, the Ministry of Trade reported that post-clearance company audits and secondary declaration controls had resulted in TRY 28.7 billion in additional assessments and penalty decisions during the preceding two and a half years. The amount recorded in the first six months of 2026 alone was TRY 8.3 billion. (https://ticaret.gov.tr)

Foreign importers should therefore treat an underpayment finding as a legal and financial dispute requiring immediate analysis rather than simply an accounting adjustment.

What Does “Underpaid Customs Duties” Mean?

An underpayment exists where the customs duties legally payable on an import exceed the amount actually assessed or paid.

For example, an importer declares goods under a tariff classification carrying a 3% customs duty. During an inspection, customs concludes that the goods should have been classified under a tariff heading carrying a 10% duty.

The difference may result in an additional assessment.

The same problem can arise where the tariff classification itself is correct but the customs value was understated.

In other cases, customs may conclude that preferential origin treatment should never have been granted.

Each scenario requires a separate legal analysis because the reason for the underpayment can affect both the additional duty and the penalty.

How Can Turkish Customs Discover an Underpayment?

The discrepancy can be discovered during physical examination, documentary controls, secondary examination of a customs declaration or a post-clearance company audit.

The fact that goods were previously released does not prevent subsequent customs scrutiny.

Turkey has increasingly developed risk-based systems for reviewing historical declarations. The Ministry’s July 2026 enforcement figures confirm that secondary controls and post-clearance audits are being actively used to identify irregular customs and foreign-trade transactions. (https://ticaret.gov.tr)

Accordingly, foreign companies should not regard customs clearance as permanently closing the declaration.

What Happens Immediately After Customs Finds the Difference?

The first issue is identifying exactly what customs believes was incorrect.

The company should determine the original declaration, the position adopted by customs, the resulting duty difference and the legal provisions relied upon.

The authority may conclude, for example, that the customs value was TRY 10 million rather than TRY 7 million.

Alternatively, it may accept the declared value but conclude that the HS classification was incorrect.

These are completely different disputes.

The importer should obtain the underlying calculation rather than focusing only on the total amount demanded.

Additional Customs Duty Assessment

Where the inspection establishes that customs duties were underpaid, the administration may assess the unpaid difference.

The importer should independently verify the calculation.

This means reconstructing the transaction from the original declaration and determining what duties would legally have been payable if the customs authority’s position were correct.

Depending on the import, the financial impact may involve ordinary customs duty as well as import VAT, additional customs duty and other import-related financial obligations.

The 2026 Import Regime continues to provide for additional financial obligations and confirms that the customs-law procedural framework applies to them. (https://ticaret.gov.tr)

Administrative Penalties Can Be Much Larger Than the Tax Difference

Foreign companies should pay particular attention to the penalty calculation.

An underpayment does not necessarily expose the company only to the missing duty.

For example, the Ministry’s customs valuation guidance explains that where goods subject to ad valorem duties have been declared at a deficient value and the discrepancy is identified through examination, inspection or post-clearance control, Article 234/1(b) of Customs Law No. 4458 may require collection of the deficient import duties together with a monetary penalty calculated by reference to the tax difference. (https://ticaret.gov.tr)

According to the Ministry’s current guidance, the ordinary rule for the valuation violation described there is a penalty equal to three times the duty difference, subject to the specific statutory exceptions. (https://ticaret.gov.tr)

This means a relatively modest customs underpayment can potentially create a substantially larger total exposure once penalties are included.

Example: Understated Customs Value

Assume a foreign company imports machinery and declares a customs value of EUR 400,000.

Customs subsequently determines that qualifying royalties should have been included and calculates the correct customs value as EUR 500,000.

The authorities may calculate the additional import duties attributable to the EUR 100,000 difference.

A separate administrative penalty may then arise under the applicable customs provision.

But before accepting the assessment, the importer should examine whether the royalty was legally required to be included in customs value.

The Ministry confirms that qualifying royalties and license fees are included only under specified conditions, and additions to the transaction price must be based on objective and quantifiable data. (https://ticaret.gov.tr)

Therefore, the calculation may be challengeable even though customs has characterized it as an “underpayment.”

Not Every Royalty Belongs in Customs Value

This distinction is important for foreign brands and multinational groups.

Customs may discover a royalty agreement during an audit and conclude that previous declarations were undervalued.

But the existence of a royalty payment does not automatically resolve the issue.

The Ministry’s customs valuation guidance requires the statutory conditions to be satisfied, including the necessary relationship between the royalty or license fee and the imported goods and the applicable condition-of-sale requirement. (https://ticaret.gov.tr)

The underlying license, supply and distribution agreements should therefore be examined before accepting an additional assessment.

Incorrect HS Code

Tariff classification is another major source of underpaid customs duties.

Suppose an importer has classified an industrial component under a tariff heading carrying a lower duty.

Customs later concludes that another tariff heading applies.

The company should not automatically accept the new classification.

The analysis should examine the product’s objective technical characteristics, composition, intended function, tariff wording, section and chapter notes and applicable classification principles.

If customs’ alternative classification is wrong, both the additional duty and related penalty may be challengeable.

One Wrong HS Code Can Affect Hundreds of Imports

This is where post-clearance investigations become financially dangerous.

Suppose the disputed product was imported monthly for three years.

A TRY 150,000 duty difference on one declaration may appear manageable.

But if the same classification was used in 100 declarations, the potential historical exposure can become substantial.

The company should therefore immediately identify every declaration using the same tariff classification.

Do not wait for customs to expand the investigation.

Incorrect Country of Origin

Underpaid duties may also result from an origin problem.

An importer may have received preferential tariff treatment because the goods were declared as having qualifying origin.

Customs may subsequently conclude that the goods did not satisfy the relevant origin rules or that the documentation was invalid.

The company should distinguish between a documentation problem and a substantive origin problem.

A defective certificate does not necessarily present the same legal issue as goods that actually fail to satisfy the relevant origin requirements.

Additional Customs Duties and Origin

Origin mistakes can become especially expensive where additional customs duties or trade-defense measures depend on the country of origin.

The importer should therefore determine precisely which financial obligations change if customs’ origin position is accepted.

The calculation should not be limited to the ordinary customs duty.

Additional customs duties, anti-dumping duties and other applicable financial measures may need separate review.

Incorrect Import VAT

Underpaid import VAT can also lead to customs consequences.

The Ministry states that where an incorrect VAT rate results in deficient import VAT, Article 234/1(a) of Customs Law No. 4458 applies. (https://ticaret.gov.tr)

The company should therefore examine whether the alleged discrepancy concerns customs value, the applicable VAT rate or another component of the import VAT base.

This distinction can affect the legal basis of the assessment and penalty.

Missing Import Controls Can Be More Serious

Sometimes customs discovers not merely an underpayment but that goods should have been subject to a required import authorization or institutional control.

This creates a different category of risk.

The Ministry’s import guidance explains that where goods were declared as though they were not subject to required institutional controls, the issue may be identified during inspection or post-clearance controls. In specified circumstances involving an adverse control result or uncontrolled goods treated as controlled, Article 235 consequences can apply, including substantially more serious sanctions. (https://ticaret.gov.tr)

Accordingly, companies should first determine whether the case is truly a tax-underpayment dispute or a broader import-compliance violation.

What Documents Should the Importer Collect?

The company should immediately preserve the entire customs file.

Relevant documents may include the customs declaration, commercial invoice, purchase agreement, purchase orders, payment records, freight documents, insurance records, technical product specifications, tariff classification analyses, origin certificates, supplier declarations, license agreements and royalty calculations.

For related-party transactions, intercompany agreements and pricing documentation may also be important.

The documents should be reviewed together rather than independently.

Review the Customs Authority’s Calculation

Never assume the numerical calculation is correct merely because the underlying issue may exist.

The company should separately verify the customs value, tariff classification, duty rate, origin, additional duties, VAT and penalty calculation.

One error can compound another.

For example, customs may correctly identify an omitted payment but incorrectly conclude that the entire payment belongs in customs value.

Or it may correctly identify a classification problem but apply the wrong historical duty rate.

The assessment should therefore be reconstructed declaration by declaration.

Does an Innocent Mistake Eliminate the Customs Duty?

Generally, the fact that an underpayment resulted from an innocent error does not automatically mean the underlying customs duty disappears.

The tax and penalty questions should be analyzed separately.

However, the nature of the error can be highly relevant when determining which penalty provision applies, whether an exception applies, whether the company can use a particular procedural mechanism and whether any allegation of intentional misconduct is sustainable.

Companies should therefore avoid treating “we made an innocent mistake” as the entire legal defense.

What If the Customs Broker Made the Error?

Foreign companies frequently rely on customs brokers to prepare declarations.

If the broker selected the wrong tariff code or entered incorrect information, the broker’s potential responsibility should be investigated.

But blaming the broker does not necessarily resolve the customs authority’s claim against the persons legally responsible under customs legislation.

Two separate issues should therefore be considered: first, the defense against customs; second, whether the importer has a contractual or professional claim against the broker.

What If the Foreign Supplier Provided Incorrect Information?

A similar issue arises where a supplier gives the importer an incorrect HS code, false or inaccurate origin information or incomplete valuation information.

The customs liability must first be analyzed under Turkish customs law.

Separately, the importer should examine whether the supply agreement contains warranties or indemnities covering customs losses caused by incorrect supplier information.

For high-value imports, these clauses can become commercially significant.

Can the Importer Challenge the Additional Assessment?

Yes.

A customs finding is not beyond challenge simply because it followed an inspection.

The importer should determine whether the factual finding and legal methodology are correct.

Under Article 242 of Customs Law No. 4458, customs duties, penalties and administrative decisions notified to the person concerned can generally be challenged through an administrative objection within 15 days of notification. Ministry materials reproduce this 15-day objection framework. ([https://ticaret.gov.tr][6])

This deadline is extremely important.

The 15-Day Period Can Disappear Quickly

Foreign companies often lose valuable time because the customs decision moves through several internal levels.

The customs broker receives the document.

It sends it to the logistics department.

Logistics sends it to finance.

Finance sends it to management.

Management sends it to foreign headquarters.

Headquarters then seeks legal advice.

By that stage, much of the objection period may already have elapsed.

The notification date should therefore be recorded immediately and legal review should begin at once.

What Should a Customs Objection Argue?

The objection should attack the specific basis of the assessment.

If the dispute concerns classification, explain why the tariff position adopted by customs is incorrect.

If it concerns customs value, demonstrate why the declared transaction value or valuation methodology complied with the applicable rules.

If it concerns origin, submit the manufacturing and origin evidence.

If customs has included royalties, explain why the statutory requirements for inclusion are or are not satisfied.

A generic statement that “the assessment is excessive” is unlikely to be an effective customs defense.

Can the Importer Request Customs Settlement?

Potentially, yes, depending on the assessment and penalty concerned.

The Ministry states that notified customs duty receivables and penalties arising from differences between the declaration and customs’ determination can fall within the customs settlement mechanism. (https://ticaret.gov.tr)

According to the Ministry’s current published guidance, applications involving amounts up to and including TRY 3 million fall within the authority of regional settlement commissions, while amounts exceeding TRY 3 million are handled by the Central Settlement Commission. (https://ticaret.gov.tr)

The settlement route should be considered strategically rather than automatically.

Objection or Settlement?

This decision can materially affect the case.

If the importer has strong technical evidence proving that customs used the wrong tariff classification or unlawfully increased customs value, challenging the assessment may be preferable.

If there is genuine uncertainty and substantial penalty exposure, settlement may deserve consideration.

The company should examine the procedural consequences before choosing a route.

Ministry guidance indicates that customs settlement is designed to resolve disputes over additional assessments and penalties without resorting to litigation. (Doguakdeniz Ticaret Müdürlüğü)

What Happens If the Importer Does Nothing?

Ignoring the assessment can be costly.

Ministry materials concerning collection explain that customs duties become final where the applicable objection or judicial challenge periods expire without the required challenge. Where litigation is pursued, collection consequences depend on the procedural outcome specified in the customs framework. ([https://ticaret.gov.tr][9])

Therefore, a company that intends to dispute the assessment should not simply wait for a payment demand.

Procedural rights must be exercised within the applicable periods.

Can the Case Go to Court?

Yes.

Where the administrative objection does not resolve the dispute in the importer’s favor, judicial remedies may be available before the competent administrative court subject to the applicable procedural requirements and deadlines.

The court can examine the legality of the customs assessment and related administrative penalties.

Technical evidence can be decisive, particularly in tariff classification, valuation and origin cases.

The company should therefore begin building the evidentiary file before litigation starts.

Could Underpaid Duties Lead to Criminal Proceedings?

Not every underpayment constitutes a criminal offense.

Many cases remain customs-tax and administrative-penalty disputes.

However, the Ministry’s customs valuation guidance expressly notes that the provisions of Anti-Smuggling Law No. 5607 remain reserved. (https://ticaret.gov.tr)

Where authorities allege false documents, deliberate concealment, fraudulent origin declarations, intentional undervaluation or another potentially criminal scheme, separate criminal-law analysis may therefore become necessary.

An ordinary classification disagreement should not automatically be treated as equivalent to intentional smuggling.

Do Not Make Unnecessary Admissions During an Inspection

Companies should cooperate with lawful customs requests, but explanations should be accurate and coordinated.

An employee unfamiliar with customs valuation might describe an intercompany payment incorrectly.

A finance employee might call a payment a royalty even though the contract characterizes it differently.

A logistics employee may describe a supplier’s country as the product’s origin even though the goods were manufactured elsewhere.

Statements made during an investigation can affect the subsequent dispute.

Responses should therefore be based on verified documents.

Conduct a Historical Exposure Review

Once customs finds one underpayment, the company should immediately determine whether the same issue exists elsewhere.

Search previous declarations for the same HS code, supplier, product, origin, valuation method, royalty structure and exemption.

Then quantify the potential exposure.

Management should know whether the investigation concerns TRY 500,000 or could expand into a multi-million-lira historical customs dispute.

2026 Enforcement Risk Is Increasing

The current enforcement figures make this particularly important.

The Ministry reported TRY 6.8 billion in additional assessments and penalties from secondary and post-clearance controls in 2024 and TRY 13.6 billion in 2025. For the first six months of 2026, the figure had already reached TRY 8.3 billion. (https://ticaret.gov.tr)

In 2025 alone, 224,738 customs declarations underwent secondary control, with irregularities identified in 49,975 declarations filed by 7,410 companies. (https://ticaret.gov.tr)

These figures demonstrate that retrospective customs review has become a major enforcement mechanism.

20-Step Action Plan After Customs Finds Underpaid Duties

1. Obtain the inspection finding and formal customs decision.
2. Record the notification date immediately.
3. Identify the declarations affected.
4. Determine why customs says duties were underpaid.
5. Separate the additional duty from administrative penalties.
6. Recalculate the assessment independently.
7. Review the HS classification.
8. Review customs valuation.
9. Check royalties and license fees.
10. Verify country of origin.
11. Review preferential tariff treatment.
12. Check additional customs duties and trade-defense measures.
13. Review import VAT calculations.
14. Collect supplier and customs broker documentation.
15. Identify all historical declarations involving the same issue.
16. Calculate the company’s total potential exposure.
17. Determine whether the 15-day administrative objection should be filed.
18. Evaluate customs settlement where legally available and strategically appropriate.
19. Assess judicial remedies if the administrative challenge fails.
20. Correct the customs compliance process for future imports.

The central point is that an inspection finding underpaid customs duties is the beginning of the legal process, not necessarily the final determination of liability. The importer should verify the underlying customs position, the amount of the additional assessment, the statutory basis of any penalty and the procedural remedies available before accepting or paying the claim.

Frequently Asked Questions

What happens if Turkish customs discovers that I paid too little duty?

Customs may issue an additional assessment for the deficient amount and, depending on the nature of the violation, an administrative monetary penalty. The applicable penalty depends on why the underpayment occurred.

Can customs charge more than the unpaid tax?

Yes. For example, Ministry guidance concerning deficient customs value under Article 234/1(b) describes circumstances in which the duty difference is collected together with a penalty calculated as three times that difference, subject to statutory exceptions. (https://ticaret.gov.tr)

Can I challenge the customs inspector’s finding?

Yes. Where the finding results in a notified customs assessment, penalty or administrative decision, the available administrative objection procedure should be examined immediately.

How long do I have to object?

Article 242 provides a 15-day administrative objection period for notified customs duties, penalties and administrative decisions. ([https://ticaret.gov.tr][6])

What if the underpayment resulted from the wrong HS code?

The importer should verify whether customs’ alternative classification is legally correct. If the authority’s classification is wrong, the resulting additional duties and related penalties may be challenged.

What if my customs broker made the mistake?

The broker’s responsibility may need separate examination, but this does not automatically eliminate the customs assessment against persons legally responsible for the import transaction.

Can underpaid duties be settled without litigation?

Potentially. Turkey has a customs settlement mechanism covering specified additional customs duty receivables and penalties. Eligibility and strategic consequences should be checked before applying. (https://ticaret.gov.tr)

Can customs investigate previous imports after finding one mistake?

Yes. This is particularly important where the same classification, valuation methodology, origin position or exemption was repeatedly used. Turkey actively conducts secondary and post-clearance reviews of historical declarations. (https://ticaret.gov.tr)

Does an underpayment automatically mean customs smuggling?

No. Many underpayment cases are administrative customs disputes. However, Anti-Smuggling Law No. 5607 may become relevant where the facts potentially satisfy its separate requirements. (https://ticaret.gov.tr)

Should foreign importers review earlier declarations immediately?

Yes. A finding affecting one shipment can reveal a repeated compliance issue. An immediate historical review allows the company to understand its total potential exposure and prepare its defense before the investigation expands.

Client-Focused Legal Support for Underpaid Customs Duty Disputes in Turkey

When Turkish customs identifies underpaid duties, foreign importers should first determine whether the authority’s underlying conclusion is legally correct. An additional assessment may result from tariff classification, customs valuation, origin, import VAT, additional customs duties, royalties or another customs issue, and each requires a different defense.

The size of the penalty also requires separate scrutiny. In customs valuation cases, for example, Ministry guidance confirms that Article 234/1(b) can result in collection of the deficient import duties together with a penalty calculated by reference to the tax difference. (https://ticaret.gov.tr)

Timing is equally important. The administrative objection period under Article 242 is generally 15 days from notification, making immediate review essential for foreign companies whose customs decisions may otherwise spend valuable time circulating between brokers, local management and overseas headquarters. ([https://ticaret.gov.tr][6])

The broader 2026 enforcement environment should also be considered. The Ministry of Trade reported TRY 28.7 billion in additional assessments and penalties from post-clearance and secondary controls during the preceding two and a half years, confirming the increasing importance of retrospective customs compliance. (https://ticaret.gov.tr)

Fırat Fesih Kaya Law Office assists foreign companies and international importers with underpaid customs duty investigations, additional customs assessments, customs penalties, HS classification disputes, customs valuation disputes, origin investigations, post-clearance audits, customs settlement, administrative objections and customs litigation in Turkey.

Phone: +90 312 434 22 22
Mobile: +90 532 769 22 22
Email: info@firatfesihkaya.av.tr
Address: Mevlana Boulevard No: 221, Yıldırım Tower, Balgat, Çankaya, Ankara, Turkey