What is an ITIN?
An ITIN (Individual Taxpayer Identification Number) is a nine-digit tax processing number issued by the IRS to individuals who are required to have a U.S. taxpayer identification number but are not eligible for a Social Security Number. ITINs always begin with the digit 9 and are formatted XXX-XX-XXXX, mirroring the SSN format.
Who needs an ITIN?
ITINs are issued to non-resident aliens required to file a U.S. tax return, U.S.-resident aliens filing under tax-residency rules, dependents/spouses of U.S. citizens or residents, foreign investors with U.S.-source income subject to withholding, and foreign students/scholars on F, J, M or Q visas without work authorisation. Non-U.S. founders, angels and limited partners in U.S. funds commonly need an ITIN to receive K-1s and claim treaty benefits.
Application process
ITIN applications use Form W-7 filed with the IRS, typically accompanied by an original or certified-by-issuing-agency identity document (passport is preferred) and the U.S. tax return for which the ITIN is needed. Applications can be filed via IRS Certified Acceptance Agents (CAAs) or through IRS Taxpayer Assistance Centers; CAAs can verify originals and return them to the applicant.
Expiration and renewal
ITINs not used on a federal tax return for three consecutive years expire automatically. The IRS also periodically requires renewal of ITINs with certain middle digits. Expired ITINs must be renewed using Form W-7 before they can be used on a subsequent return.
Limitations
An ITIN does not authorise the holder to work in the United States, does not confer immigration status, does not entitle the holder to Social Security benefits, and does not constitute valid identification outside the federal tax system. It is a tax processing tool only.