EIN vs SSN vs ITIN: Which Tax ID Do You Need to Verify for 1099 Compliance?
When a new vendor submits their W-9, you need to know whether to expect an EIN, SSN, or ITIN, and whether the number provided matches the vendor’s entity type.
Filing a 1099 with the wrong TIN type triggers IRS penalties and CP2100 notices.
As the payer, your responsibility is to collect the correct TIN for the vendor and verify it before filing. By the end of this guide, you’ll have a clear framework for handling each vendor type.
EIN vs SSN vs ITIN: Why the TIN Type on a W-9 Determines Your 1099 Filing Risk
The IRS requires the TIN to match both the legal name and the entity type under which it was registered. Filing a 1099 with an SSN for a corporation, or submitting an EIN in an incorrect format, will result in a name/TIN mismatch in IRS records.
Three outcomes follow if you get it wrong:
- The IRS rejects the name/TIN match and issues a CP2100 notice.
- Penalties range from $60 to $680 per form, depending on when the error is corrected. As of 2026, the penalty tiers are $60 (corrected within 30 days), $130 (corrected by August 1), $340 (after August 1 or uncorrected), and $680 for intentional disregard.
- Backup withholding at 24% applies to future payments until a correct TIN is received.
The payer is responsible for collecting the correct W-9, confirming the TIN type matches the vendor entity, and verifying the information before filing.
EIN: The TIN You Will Most Often Receive From Business Vendors
An Employer Identification Number (EIN) is issued by the IRS and formatted as XX-XXXXXXX. Corporations, LLCs, partnerships, nonprofits, and any business with employees typically provide an EIN on their W-9, not an SSN.
Watch for: Sole proprietors who provide an SSN instead of an EIN (or vice versa). Both may be valid, but the number must match IRS records for the correct name.
EIN Verification: Run the EIN against the vendor’s legal business name using a real-time verification tool like TINCheck by Sovos. Perform verification before payment, not after a mismatch notice.
1099 filing tip: Enter the EIN in the XX-XXXXXXX format. If a vendor submits nine digits without a hyphen, or uses an SSN-style format, ask for a corrected W-9. Formatting errors can result in a no-match even when the number is valid.
SSN: When You Are Paying Individual Vendors, Freelancers, or Sole Proprietors
A Social Security Number (SSN) is issued by the Social Security Administration and formatted as XXX-XX-XXXX.
Individual vendors typically provide an SSN. This includes sole proprietors, single-member LLCs not treated as corporations, independent contractors, and freelancers. The 1099 should reflect the SSN unless the vendor has registered and provided an EIN.
Important: The SSN must be verified against the individual’s legal name, not their DBA or trade name. If the W-9 says “John Smith doing business as JS Design,” the TIN verification must run against “John Smith”. That’s the name tied to the SSN in IRS records.
On your W-9 storage process: SSNs are sensitive personal data. Limit access to only the team members who genuinely need it, and make sure your document storage is secure.
1099 filing: Report SSNs in the XXX-XX-XXXX format. Do not use EIN formatting.
ITIN: What to Do When a Foreign or Non-Resident Vendor Provides This Number
An Individual Taxpayer Identification Number (ITIN) is issued by the IRS and formatted as 9XX-XX-XXXX. It is used by non-U.S. individuals with U.S. tax obligations, such as foreign individual contractors or non-resident alien vendors, who are not eligible for an SSN.
Note: ITINs expire if not used on a federal tax return for three consecutive years. Certain ITIN ranges have already expired regardless of use. An expired ITIN fails TIN matching and requires an updated W-9 before filing.
Tax reporting only: An ITIN does not authorize work in the U.S. It is used only for tax reporting.
For foreign business entities (not individuals): You should collect a Form W-8BEN-E, not a W-9. These entities are generally outside standard 1099 reporting and may be subject to 30% withholding rate unless a tax treaty applies.
The AP Team’s Decision Matrix: Which TIN to Collect by Vendor Type
Use this table during vendor onboarding to confirm you’re asking for the right form and the right TIN type:
| Vendor Type | Form to Collect | TIN Type | 1099 TIN Format | Name to Use on W-9 |
| US Corporation or LLC | W-9 | EIN | XX-XXXXXXX | Legal business name |
| Partnership | W-9 | EIN | XX-XXXXXXX | Legal business name |
| Sole Proprietor / Individual Contractor | W-9 | SSN or EIN | XXX-XX-XXXX or XX-XXXXXXX | Individual legal name |
| Non-US Individual | W-9 | ITIN | 9XX-XX-XXXX | Individual legal name |
| Non-US Company | W-8BEN-E | N/A | Not applicable | Legal business name (per W-8BEN-E) |
Key rule: The name on the W-9 must match the name associated with the TIN in IRS records. DBA names will result in mismatches.
The Most Common TIN Mismatches That Trigger IRS Penalties
Common TIN mismatches include:
- DBA name instead of legal entity name
- EIN submitted in SSN format
- SSN provided under a business name instead of an individual name
- Expired ITIN
- Outdated EIN due to ownership or structural changes
Each mismatch can result in a CP2100 notice, correction filings, and penalties. Unresolved errors may also trigger backup withholding on future payments.
What to Do If the TIN You Collected Is Incorrect
If a TIN fails verification, move quickly:
- Request a corrected W-9 immediately
- Do not file with an incorrect TIN
- Document all outreach, including dates, methods, and responses
- Re-run verification after correction
- Apply backup withholding at 24% if a valid TIN is not provided
- Flag the vendor record in your system
How to Verify the Correct TIN Before Filing Any 1099
Verification should occur during onboarding, before filing season, and after any vendor updates.
Step 1: Collect a completed W-9
The form needs a legal name, a TIN, and a signature. An unsigned W-9 is not a valid backup withholding exemption certificate.
Step 2: Run TIN verification
Use a real-time verification tool that supports both single-record and bulk checks. TINCheck validates vendor records before filing.
Step 3: Review the match result
A match means you can proceed. A no-match means you need to investigate before the 1099 goes out.
Step 4: Resolve mismatches before filing
Contact the vendor, request an updated W-9, and re-verify. Don’t file and hope for the best.
Step 5: Keep your verification records
Maintain an audit trail showing the date verified, the result, and any follow-up. This documentation matters if you ever receive a B-Notice and need to demonstrate due diligence.
Get Your Vendor TINs Right Before Filing Season
Each TIN type maps to a specific vendor category, name format, and verification requirement. A mismatch results in penalties, corrections, and additional administrative work.
Pre-filing TIN verification reduces these risks and improves filing accuracy.
TINCheck by Sovos validates vendor TINs in real time, individually or in bulk, before filing.
Frequently Asked Questions
What is the difference between an EIN, SSN, and ITIN for 1099 filing purposes?
An EIN is used by business entities like corporations and LLCs. An SSN is used by individual contractors and sole proprietors. An ITIN is used by non-U.S. individuals with U.S. tax obligations. As the payer, you must collect and verify the TIN that matches the vendor’s entity type.
What happens if I file a 1099 with the wrong TIN type?
A mismatched TIN triggers a name/TIN mismatch, leading to a CP2100 notice. You may need to file corrections and could face penalties ranging from $60 to $680 per form. Backup withholding at 24% may also apply to future payments.
Do ITINs expire, and how does that affect my 1099 filing?
Yes. ITINs expire if not used on a federal tax return for three consecutive years, and certain ranges have already expired. An expired ITIN will fail TIN matching, so you should request an updated W-9 before filing to avoid mismatches and penalties.
Which TIN should a sole proprietor provide on their W-9, their SSN or their EIN?
A sole proprietor can provide either an SSN or an EIN. Both are valid, but the TIN must match the name it was registered under with the IRS. Always verify the number against the correct legal name before filing a 1099.
How do I verify a vendor’s TIN before filing a 1099?
Collect a completed, signed W-9 with the vendor’s legal name and TIN. Then run the name/TIN combination through a real-time verification tool. Resolve any mismatches before filing, and keep records of verification results for audit and compliance purposes.
Can a non-US citizen get an ITIN number?
Yes. Non-U.S. individuals who are not eligible for an SSN can obtain an ITIN for tax reporting. If a vendor is eligible for an SSN, they must use that instead. ITINs are used only for tax reporting and do not authorize work in the U.S.