A unique number (such as the EIN, ITIN, or SSN) used by the IRS to identify individuals and businesses for tax purposes in the United States.
What is a TIN?
A Taxpayer Identification Number (TIN) is a unique number assigned by the U.S. Internal Revenue Service (IRS) to individuals and businesses for use in tax filings, reporting, and official identification. Every U.S. taxpayer—whether a person or an entity—must use a TIN when filing tax returns, opening bank accounts, applying for licenses, or reporting income to the IRS.
There are several types of TINs, depending on the status and purpose of the individual or entity:
1. Social Security Number (SSN)
Issued to: U.S. citizens and eligible U.S. residents
Format: 9 digits (e.g., 123-45-6789)
Used for: Individual tax filings, employment, and benefits
Note: Non-U.S. persons are generally not eligible for an SSN unless they are authorized to work in the U.S.
2. Employer Identification Number (EIN)
Issued to: Businesses, including LLCs, corporations, and partnerships
Format: 9 digits (e.g., 12-3456789)
Used for: Filing business taxes, opening a U.S. business bank account, hiring employees
Note: An EIN is often required even for single-member LLCs owned by non-U.S. persons, especially when dealing with payment processors or the IRS.
3. Individual Taxpayer Identification Number (ITIN)
Issued to: Non-U.S. individuals who are not eligible for an SSN but still need to file a U.S. tax return
Format: 9 digits (e.g., 9XX-7X-XXXX)
Used for: U.S. tax reporting by foreign owners, investors, or dependents
Note: ITINs are obtained by filing Form W-7 with supporting documents. For example, a non-U.S. founder of a U.S. LLC might need an ITIN to comply with tax obligations or claim tax treaty benefits.
For businesses, the EIN is the most common type of TIN and is often required when:
- Filing federal or state taxes
- Opening a U.S. business bank account
- Applying for licenses or permits
- Hiring U.S. employees
- Registering for a sales tax permit
Individuals (like foreign founders or investors) may need an ITIN to:
- Report U.S. income
- Claim tax treaty benefits
- Receive Form 1042-S or Form K-1
- File Form 1040-NR as a non-resident
In summary, a TIN is essential for almost every U.S. tax-related activity. While U.S. citizens typically use SSNs, non-U.S. founders are more likely to interact with EINs (for their companies) and ITINs (for themselves as individuals). Understanding which type of TIN is needed—and how to obtain it—is critical for staying compliant with U.S. tax laws.
