A foreign taxpayer identification number is the tax ID your home country’s government assigns you, and U.S. banks, brokerages, and other withholding agents generally need it before they’ll pay you U.S.-source income at a treaty-reduced rate or without a flat 30% withholding. If you’re a non-U.S. person receiving dividends, interest, royalties, or similar income from U.S. sources, expect to see a line asking for it on Form W-8BEN or W-8BEN-E.
What Counts as a Foreign TIN
Every country that collects taxes issues some kind of number to track who owes what. The name and format change at every border. India uses a Permanent Account Number (PAN), a ten-character alphanumeric code. The United Kingdom issues a National Insurance Number for employees and a Unique Taxpayer Reference for self-assessment filers. Canada assigns a nine-digit Social Insurance Number. Whatever your country calls it, the function is the same: it links your financial activity to your tax record at home.
From the U.S. side, “foreign TIN” simply means the TIN issued by a country other than the United States. When a U.S. financial institution asks for yours, that’s what they want.
When a U.S. Payer Will Ask for It
Two U.S. rules generate almost every foreign TIN request: FATCA account reporting and income tax treaty claims. Both run through the W-8 forms.
The Foreign Account Tax Compliance Act requires U.S. withholding agents to collect identifying information from foreign account holders, and it’s built into Form W-8BEN for individuals and Form W-8BEN-E for entities.1Internal Revenue Service. Summary of Key FATCA Provisions A foreign TIN is generally required on those forms when you hold a financial account at a U.S. office of a financial institution and receive U.S.-source income reportable on Form 1042-S.2Internal Revenue Service. Instructions for Form W-8BEN
The second trigger is treaty benefits. If your country of residence has an income tax treaty with the United States, you may qualify for a reduced rate of withholding on dividends, interest, royalties, and other U.S.-source income. To claim it on Form W-8BEN, you generally need to provide either a foreign TIN or a U.S. taxpayer identification number such as an ITIN. Without one of the two, the withholding agent typically cannot apply the treaty rate. Limited exceptions exist for certain publicly traded securities and registered mutual funds, but for most portfolio income the rule holds.2Internal Revenue Service. Instructions for Form W-8BEN
What Leaving It Blank Costs You
If you file a Form W-8BEN without a foreign TIN on line 6a and don’t check box 6b or attach a reasonable explanation, the withholding agent is supposed to treat the form as invalid for U.S.-source income reported on Form 1042-S.3Internal Revenue Service. Instructions for the Requester of Forms W-8BEN, W-8BEN-E, W-8ECI, W-8EXP, and W-8IMY
An invalid form pushes the payer into the presumption rules. Under chapter 3 of the Internal Revenue Code, that means withholding at the statutory 30% rate on the full payment, with no treaty reduction.4Internal Revenue Service. Tax Withholding Types A treaty that would otherwise drop your dividend rate to 15% or zero simply doesn’t apply until the form is fixed. Some of that withholding may be recoverable by filing a U.S. return, but the cleaner path is providing the TIN up front.
If You Don’t Have One
Not every country issues TINs, and not every resident of a country that does is required to hold one. The W-8BEN accounts for both cases.
Line 6b on the individual form lets you check a box stating that you are not legally required to obtain a TIN from your country of residence, which covers situations where your country doesn’t issue them at all.2Internal Revenue Service. Instructions for Form W-8BEN The IRS publishes a list of jurisdictions it recognizes as non-issuing, which includes Bermuda, the British Virgin Islands, and the Cayman Islands, among others.5Internal Revenue Service. List of Jurisdictions That Do Not Issue Foreign TINs If your country is on that list, checking 6b resolves the question.
If your country does issue TINs but you’re personally exempt, write a brief explanation in the margin of the form or attach a separate statement describing why. Some countries exempt residents below certain income or age thresholds; a plain-language note is usually enough.
When neither option fits and you still need to satisfy a U.S. payer or file a U.S. return, an Individual Taxpayer Identification Number (ITIN) can serve in place of a foreign TIN. The ITIN is a nine-digit number the IRS issues to people who have a federal tax obligation but aren’t eligible for a Social Security Number, and you apply using Form W-7.6Internal Revenue Service. Individual Taxpayer Identification Number (ITIN) Form W-7 generally attaches to the front of a federal tax return, though exceptions allow it to be filed on its own when the ITIN is needed solely for third-party reporting or withholding.7Internal Revenue Service. Instructions for Form W-7 (12/2024) The IRS estimates seven weeks of processing under normal conditions, stretching to nine to eleven weeks during filing season or for overseas applications.8Internal Revenue Service. Form W-7
Foreign TINs for Business Entities
Entities file Form W-8BEN-E rather than W-8BEN. The foreign TIN goes on line 9b, and the requirement mirrors the individual rule: it’s needed when the entity holds an account at a U.S. financial institution and receives reportable U.S.-source income.9Internal Revenue Service. Instructions for Form W-8BEN-E (10/2021) Governments, central banks, international organizations, and residents of U.S. territories are exempt. Entities from non-issuing jurisdictions check box 9c, the entity counterpart of line 6b.
One point of confusion worth clearing up: a Global Intermediary Identification Number (GIIN), the 19-character code foreign financial institutions receive when they register with the IRS under FATCA, is not a substitute for a foreign TIN. The GIIN identifies an institution for FATCA reporting; the foreign TIN identifies the entity within its home country’s tax system.10Internal Revenue Service. FATCA Registration and FFI List – GIIN Composition Information
Finding or Verifying Your Number
If you’re unsure whether you have a foreign TIN or what format it takes, the most reliable source is the national tax authority in your country of residence. Some countries assign a TIN automatically at birth or when you enter the workforce; others require you to apply.
The OECD maintains an online portal that lists the TIN rules for participating jurisdictions, including the official name of each country’s TIN, its format, and the government body that issues it. It covers both individuals and entities and was last updated in February 2026.11OECD. Tax Identification Numbers The OECD treats its listings as preliminary and directs specific questions back to the relevant tax authority, but the portal is a good starting point when you’re trying to identify what your country issues and where to get it.