Apostille for U.S. Certificate of Residency: Lessons from the Ukrainian Tax Authority
Recently, the State Tax Service of Ukraine published a case that serves as yet another reminder for everyone working with international clients: the details make all the difference. The case concerned a U.S. resident who submitted IRS Form 6166 — a certificate of U.S. tax residency — to a Ukrainian tax agent without an apostille. The tax authority rejected the document for purposes of tax exemption in Ukraine.
What happened?
An American company was due to receive income from Ukraine. To avoid a 15% withholding tax on repatriated income, it had to prove its eligibility for a tax benefit under the U.S.-Ukraine Double Taxation Convention. The company submitted Form 6166 — an official document issued by the IRS. However, the form was not apostilled.
The Ukrainian Tax Authority denied the application of the tax benefit, arguing that the document lacked an apostille and, therefore, could not be considered properly legalized, as required under Ukrainian law.
Why is an apostille mandatory?
- Both Ukraine and the U.S. are parties to the 1961 Hague Convention, which means documents originating from one country must be apostilled to be valid in the other.
- The U.S.-Ukraine tax treaty does not contain a specific clause exempting documents from the legalization requirement.
- Therefore, without an apostille, Form 6166 cannot be accepted as valid proof of tax residency.
Key takeaways for GLS practice
- Every document under the microscope. Even a “standard” IRS certificate must be checked for apostille.
- Treaties are not everything. Even if a treaty provides for a tax exemption, all formal domestic legal requirements must still be met.
- Educating clients is our duty. Many companies — especially U.S. ones — are unaware of the apostille requirement. This is an opportunity to demonstrate expertise and mitigate tax risks for the client.
How can we apply this experience?
- Add a checklist of required documents for all transactions involving non-residents.
- Include a training module on apostilles for new lawyers and assistants.
- Warn clients about these types of risks at the contract planning stage.
