Individual Taxpayer Identification Number ITIN

The Individual Taxpayer Identification Number (ITIN) is a tax-only identification number issued by the US Internal Revenue Service to individuals who have a US tax filing or reporting obligation but do not qualify for a Social Security Number (SSN). It is formatted identically to an SSN as XXX-XX-XXXX but always begins with the digit 9. The ITIN does not authorize work in the US, does not provide eligibility for Social Security benefits, and does not establish immigration status; it exists solely so the IRS can process returns, withhold tax correctly, and apply tax-treaty benefits for non-resident persons. Founders of foreign-owned US LLCs typically need an ITIN if they are individually liable for filing Form 1040-NR, claiming a tax-treaty rate on Form W-8BEN, or being listed as a beneficial owner on filings that require a US TIN. ITINs are obtained by filing IRS Form W-7 alongside a federal tax return, with original or certified-copy passport documentation, either through a Certified Acceptance Agent (CAA) or directly to the IRS Austin processing center. Since 2016, ITINs that are unused for three consecutive tax years expire automatically and must be renewed.

A foreign founder typically needs an ITIN when filing personal Form 1040-NR for US-source income, claiming a reduced withholding rate under a tax treaty, applying for an EIN online (the responsible party path requires SSN or ITIN), or being named as a partner on a US partnership return. Many founders of foreign-owned single-member LLCs do not need an ITIN because the LLC itself files Form 5472 + pro-forma 1120 using its EIN, but founders who add a US-source revenue stream or become a partner in a US LLC will hit the ITIN requirement.