What is a Tax Residency Certificate and which countries require it before paying you

If you run a US startup and you have clients outside the United States, you have probably encountered a version of this situation: you send an invoice, the payment arrives short, or the client's finance team sends a message asking for something called a tax residency certificate before they will release funds.

This is not unusual. Many countries apply withholding tax to cross-border payments at their standard domestic rate unless the recipient can prove they are a tax resident of a country that has a tax treaty with the payer's country. The tax residency certificate is that proof. Without it, the foreign payer has no legal basis to apply the lower treaty rate, so they deduct at the full domestic rate and you receive less than you invoiced.

For a US startup receiving payments from India, Germany, the Netherlands, Japan, South Korea, or several other countries, a tax residency certificate can mean the difference between receiving 80% of an invoice and receiving 100% of it. Across a year of invoices, the gap is material.

This guide explains what a tax residency certificate is, what the US certificate looks like, why foreign clients require it, which countries most commonly ask for one before releasing payment, and how India's TDS framework specifically interacts with it in 2026.

What is a Tax Residency Certificate?

A tax residency certificate is an official document issued by a country's tax authority that confirms an entity or individual is a tax resident of that country for a specified tax year. It serves as proof that the certificate holder is eligible to claim benefits under bilateral tax treaties, specifically reduced or zero withholding rates on cross-border payments.

When a company in one country sends money to a company in another country, the paying country's tax authority often requires withholding tax to be deducted before the payment crosses the border. The default withholding rates for many countries are between 20% and 30% on payments like service fees, royalties, interest, and dividends. Tax treaties between countries negotiate these rates down, sometimes significantly, but the reduced treaty rate only applies when the recipient can prove they are a tax resident of the treaty partner country.

The tax residency certificate is that proof. Without one on file, the foreign payer cannot legally apply the reduced rate. They must default to the higher domestic rate, and recovering the excess becomes a refund claim process with a foreign tax authority, which is slow, paperwork-heavy, and sometimes subject to strict deadlines that are easy to miss.

A US tax residency certificate does not confirm that taxes have been paid. It does not grant any immigration status. It does not establish a legal entity in the foreign country. What it does is confirm that the holder is recognized as a US tax resident for a specific year, making them eligible for treaty protections in countries that have active income tax treaties with the United States.

The US Tax Residency Certificate: Form 6166

For a US entity or individual, the tax residency certificate is Form 6166. It is a letter printed on official US Department of the Treasury stationery, issued by the IRS after the entity or individual files Form 8802, Application for United States Residency Certification.

Form 6166 certifies that the named entity is a resident of the United States for federal income tax purposes during the requested tax year. Foreign tax authorities, banks, and payers use it to verify that the recipient qualifies for treaty benefits.

The process for obtaining Form 6166 is entirely covered in Inkle's existing guides on Form 8802 and the Form 6166 certification process, so this post focuses on what happens after you have it: which countries require it, why they require it, and what their specific procedures look like.

The one piece of timing that matters most from the application side: Form 8802 takes approximately six to eight weeks to process under normal conditions. The IRS recommends applying at least 45 days before the certificate is needed. If a client is holding a large payment pending receipt of the certificate, applying as soon as the client relationship begins rather than when the first invoice is raised is the safest approach. Applying after the client asks for it creates a window where payment is blocked for six to eight weeks while the IRS processes the application.

Why foreign countries require a Tax Residency Certificate?

Every country that has signed a bilateral income tax treaty with the United States has committed to applying reduced withholding rates on certain cross-border payments to US residents. The treaty, however, does not apply automatically. The payer's country needs confirmation that the recipient is actually a US resident before it can legally apply the treaty rate rather than its domestic rate.

Without that confirmation, applying the treaty rate exposes the payer to regulatory risk in their own country. Their tax authority could later determine that the withholding was insufficient and hold the payer liable for the shortfall. To protect themselves, payers require the recipient to provide documentation of their residency status before processing payments at the reduced rate.

The US has income tax treaties with more than 68 countries as of 2026, including India, Germany, France, the Netherlands, Japan, Canada, the UK, Australia, South Korea, China, and Singapore. Countries without US income tax treaties as of 2026 include Brazil, Argentina, Saudi Arabia, the UAE, and Singapore. For payments to US entities from any of those non-treaty countries, there is no reduced rate to claim and no certificate that would change the withholding calculation.

Countries that commonly require a Tax Residency Certificate before paying US entities

The following countries are among the most common sources of invoice delays and withheld payments for US startups with international clients, and each has specific procedures or forms that accompany the Form 6166.

India

India is the most relevant country for Inkle's audience and has among the most detailed withholding documentation requirements of any US treaty partner.

Under Section 195 of India's Income-tax Act, any Indian entity making a payment to a non-resident that is chargeable to tax in India must deduct TDS before remitting payment. The default domestic withholding rates for payments to non-residents range from 10% to 20% on royalties and fees for technical services, with higher rates on dividends and interest. Under the US-India Double Taxation Avoidance Agreement (DTAA), these rates can be reduced significantly, but the reduction requires documentation.

To claim treaty benefits on a payment from an Indian client, a US entity must provide a valid TRC confirming US tax residency, a completed Form 10F filed electronically with India's Income Tax Department, and in many cases a No Permanent Establishment (no-PE) declaration confirming that the US entity does not have a permanent establishment in India.

The Income-tax Rules 2025 made electronic filing of Form 10F mandatory for all non-residents seeking treaty relief, including those without an Indian PAN. This is a change from prior years when Form 10F could sometimes be submitted in paper form. Foreign entities that do not have and are not required to obtain an Indian PAN can now file Form 10F electronically through India's income tax portal.

The Indian Supreme Court has also clarified in recent jurisprudence that a TRC is an eligibility condition for treaty benefits but is not conclusive proof. Indian tax authorities may still scrutinize whether the US entity has genuine substance and liability to tax in the United States, particularly for payments of substantial amounts.

From FY 2026-27, Indian payers are also required to file Form 145 (replacing the earlier Form 15CA) as a remitter declaration before making outward remittances, and in applicable cases to obtain Form 146 (replacing Form 15CB) as a chartered accountant or authorized officer certificate. These new forms require the payer to declare that TDS has been correctly deducted and that treaty provisions have been properly applied.

Common payment types where Indian clients require TRC documentation: Fees for software services, SaaS subscriptions, professional services, royalties, and interest payments. The treaty article applicable to each type of payment differs: royalties fall under Article 12 of the US-India DTAA, interest under Article 11, and dividends under Article 10. Each article specifies the reduced treaty rate that applies with proper documentation.

Germany

Germany applies withholding tax on dividends, interest, and royalties paid to non-residents at domestic rates. Under the US-Germany income tax treaty, these rates are reduced. German payers require a Form 6166 from the recipient to apply the treaty rate at source. Without it, the German payer defaults to the domestic rate and the recipient must file a refund claim with the German Federal Central Tax Office, a process that can take months.

Netherlands

The Netherlands applies withholding tax primarily to dividends. The standard rate is 15%, which can be reduced under the US-Netherlands treaty. Dutch payers require proof of US residency to apply the reduced treaty rate. Form 6166 serves this purpose. EU Parent-Subsidiary Directive exemptions also apply in some structures, subject to a residency certificate confirming eligibility.

Japan

Japan applies withholding tax on dividends, interest, and royalties paid to foreign entities. The US-Japan tax treaty reduces these rates. Japanese payers require a tax residency certificate to apply treaty rates, and the documentation process in Japan is generally more formal than in most other treaty partners. The Japanese National Tax Agency has specific forms that payers complete alongside the US Form 6166 submission.

South Korea

South Korea withholds tax on dividends, interest, and royalties at domestic rates that can be reduced under the US-South Korea treaty. Korean payers typically require a Form 6166 before applying treaty rates. The Korean National Tax Service has its own verification procedures that the payer must follow alongside the certificate.

Canada

Canada applies withholding tax on dividends, interest, and royalties. The US-Canada income tax treaty is one of the most comprehensive bilateral tax agreements in the world and reduces rates significantly. Canadian payers may request a US residency certificate for larger or recurring payments, though the documentation requirements are generally less stringent than in India or Japan for routine service payments.

United Kingdom

The US-UK income tax treaty is broad and covers most categories of cross-border income. UK payers may request Form 6166 for dividend payments and royalties. The UK has its own double taxation relief procedures through HMRC, and in many cases HMRC relief can be claimed directly by the US recipient without the UK payer needing to see the certificate upfront, though having it available speeds the process.

The Practical Impact: What Happens Without a TRC

When a foreign payer does not have a valid tax residency certificate on file and applies the domestic withholding rate, the US entity has two options for recovering the excess: claim a foreign tax credit on the US corporate return, or file a refund claim directly with the foreign tax authority.

The foreign tax credit approach under Form 1116 or Form 1118 allows the US entity to offset some of the excess foreign tax against its US tax liability. However, this only provides value when the US entity has sufficient US tax liability to absorb the credit. For a pre-revenue startup with no US tax owed, the credit has no immediate value.

The refund claim approach requires filing a reclaim application with the foreign tax authority, often in the local language, with documentation that can take months to gather. Refund processing timelines vary widely. India's refund processes are known to take one to three years in many cases. Japan's processes are more predictable but still measured in months. Missing the filing deadline for a refund claim in some jurisdictions permanently forfeits the refund.

Obtaining Form 6166 before the first payment from a new foreign client is almost always significantly easier than recovering over-withheld tax after the fact. The IRS application takes six to eight weeks. A retroactive refund claim from a foreign government can take years.

VAT exemptions and other uses for a Tax Residency Certificate

While withholding tax reduction is the most common use for a tax residency certificate, the IRS explicitly notes that Form 6166 can also be used for VAT exemption purposes in certain countries, though it only certifies US federal income tax residency, and each country's VAT exemption requirements may involve additional documentation beyond the certificate itself.

Some international banks also require IRS residency certification before opening accounts for US entities. Certain foreign tax authorities require it as part of standard compliance documentation for foreign vendors. European Union countries in particular may ask for it as part of their GDPR and financial services vendor documentation processes, even for payments that are not subject to withholding tax.

The 2026 update: India's New Remittance Forms

For US companies receiving payments from Indian clients, one of the most operationally significant changes in 2026 is India's transition from Form 15CA and Form 15CB to the new Form 145 and Form 146 under the Income-tax Rules 2026, effective from FY 2026-27.

Form 145 replaces Form 15CA as the remitter's declaration that the payer files electronically before making an outward remittance. Form 146 replaces Form 15CB as the chartered accountant or authorized officer certificate. Indian banks are now required to accept only the new forms.

For US companies receiving payments from India, the practical impact is that Indian clients may ask for updated documentation packages to support the new forms. The core TRC requirement remains unchanged, but the surrounding documentation pack, including Form 10F, the no-PE declaration, and the treaty article citation, needs to be prepared and ready for each payment. Preparing this documentation once per year for a given client relationship and updating it as the Form 6166 is renewed reduces friction on individual payments throughout the year.

Obtaining Form 6166, completing Form 10F for Indian clients, preparing no-PE declarations, and managing the documentation requirements for each foreign market where you receive payments is exactly the kind of cross-border compliance work Inkle handles. Book a demo with Inkle to make sure your treaty benefit documentation is in order before your next payment cycle with an international client.

Frequently Asked Questions

Why is my Indian client asking for a tax residency certificate before paying my invoice?

Under Section 195 of India's Income-tax Act, Indian entities making payments to non-residents must deduct TDS before remitting payment if the sum is chargeable to tax in India. The standard domestic withholding rates are 10% to 20% for service fees and royalties. To apply the lower rate available under the US-India DTAA instead of the domestic rate, the Indian payer needs documentation proving you are a US tax resident. That documentation is Form 6166, the US tax residency certificate. Without it, the Indian payer must withhold at the higher domestic rate to remain compliant with Indian tax law.

How long does it take to get a US tax residency certificate?

Form 6166 is obtained by filing Form 8802 with the IRS. Processing takes approximately six to eight weeks under normal conditions, and nine to eleven weeks during peak filing season from January to April. The IRS cannot issue the certificate faster regardless of the urgency of the payment situation. If a client is requesting the certificate before releasing a payment, apply as soon as you become aware of the requirement, not after the payment is already blocked. Our detailed guide on Form 8802 and Form 6166 covers the complete application process and fees.

Can I use one Form 6166 for multiple countries?

Yes. A single Form 6166 certifies your US tax residency for a specified year and can be presented to tax authorities and payers in multiple countries during that year. You can also request Form 6166 for multiple countries at once on a single Form 8802 application. The validity period is generally one year, after which you need to apply again for the next tax year. Some countries have specific validity requirements for residency certificates, so checking the target country's specific rules before submitting is advisable.

What happens if a foreign client already withheld tax at the full domestic rate before I provided my TRC?

If withholding has already occurred at the domestic rate rather than the reduced treaty rate, you have two main options. First, you can claim a foreign tax credit on your US corporate tax return using Form 1118, which allows you to offset some or all of the excess foreign tax against your US tax liability, provided you have sufficient US tax owed to absorb the credit. Second, you can file a refund claim directly with the foreign tax authority for the difference between the domestic rate that was applied and the treaty rate you were entitled to. The refund process timelines vary significantly by country, from several months for well-organized jurisdictions to several years for others. Obtaining Form 6166 before the next payment cycle from the same client prevents the problem from recurring.