What the program checks
The IRS TIN Matching Program takes a TIN, a name, and (optionally) a TIN type, and tells you whether that combination exists in IRS records. It does not tell you the correct name for a TIN, it does not tell you the correct TIN for a name, and it does not confirm that the person handing you the W-9 is the person the TIN belongs to. It answers one question: would this pair match on a 1099?
For SSNs the IRS matches against the Social Security Administration's name records; for EINs, against its own business master file. Matching is on the first four characters of the name control the IRS derives from the name, which is why a slightly different name often still matches and a completely different one never does. The exact algorithm isn't published, but the practical rules are in the section on why real pairs mismatch.
The nine result codes
| Code | Meaning | What it usually indicates |
|---|---|---|
| 0 | TIN and name combination matches IRS records | Clear to file with this pair. |
| 1 | TIN was missing or not nine numeric digits | Format problem in your data: a blank, a dash in the wrong place, a leading zero stripped by a spreadsheet. |
| 2 | TIN entered is not currently issued | The number doesn't exist. Typo, invented number, or an EIN that was never activated. |
| 3 | TIN and name combination does not match IRS records | Both exist, but not together. The classic sole-proprietor or legal-name problem. |
| 4 | Invalid TIN matching request | A malformed record, usually in bulk files: wrong field lengths or characters. |
| 5 | Duplicate TIN matching request | The same pair was already submitted in this session or file. Not an error with the data. |
| 6 | Matched on SSN, when the TIN type was left unspecified | The pair is valid as an individual's name and SSN. |
| 7 | Matched on EIN, when the TIN type was left unspecified | The pair is valid as a business name and EIN. |
| 8 | Matched on both SSN and EIN, when the TIN type was left unspecified | Rare: the same nine digits are a valid SSN for that name and a valid EIN for that name. |
Codes 0, 6, 7 and 8 are matches. Codes 1, 2 and 3 are the data problems that will produce a CP2100 if filed. Codes 4 and 5 are about your request, not the payee.
Who can use it and how
Direct access is through IRS e-Services and is limited to payers listed in the IRS Payer Account File, which in practice means organizations that have filed one of the eligible information returns (1099-B, DIV, INT, K, MISC, NEC, OID, PATR) in the last two years. The individual using it must have an IRS online account verified through ID.me and be authorized by a principal of the organization. New businesses, and businesses that have not yet filed, cannot enroll until they have a filing history.
Two modes are offered. Interactive checks up to 25 name/TIN pairs per request with an immediate result. Bulk accepts a fixed-format text file of up to 100,000 records and returns results within 24 hours. Both are free.
Third-party services (including the publisher of this site) access the same IRS program under their own credentials and resell the result with an API, a portal and a plain-language explanation. The match itself is the IRS's; what differs is the enrollment, the volume limits, the format and what happens after a mismatch.
Why real pairs mismatch
Most code-3 results are legitimate vendors with a paperwork problem, not bad actors. The recurring causes:
- Sole proprietor with the business name on line 1. The SSN belongs to a person, so the name must be the person's. The DBA goes on line 2. This is the single most common mismatch in AP files.
- Single-member LLC using the owner's SSN. A disregarded LLC reports under the owner's name and SSN (or the owner's EIN), not the LLC's name. If the LLC got its own EIN, then the LLC name and that EIN is the pair.
- Legal name vs. trade name. "Smith & Jones Consulting" may be registered with the IRS as "S&J Holdings Inc." The EIN matches the legal name only.
- Name changes. Marriage, divorce, corporate reorganizations. The SSA or IRS record lags, or was never updated.
- Punctuation and suffixes. Usually harmless because of name-control matching, but "The" at the start of a company name, or a trust listed under the trustee's name instead of the trust's, can break it.
- Transposed digits. A real TIN with two digits swapped is often another real TIN, which produces code 3 rather than code 2.
What to do with each result
Questions people ask
Can TIN matching tell me the right TIN for a company?
No. The IRS program only confirms or denies a pair you already have. Finding the right EIN from a company name requires a separate data source; that is what "EIN lookup" or "EIN discovery" products do.
Can I share the result with the vendor?
You can tell a vendor that the name/TIN combination they gave you doesn't match IRS records and ask for a corrected W-9. The IRS asks that TIN Matching be used only for the payer's own information-reporting purposes and not, for example, as an identity-verification service for third parties.
How often should I re-verify?
At onboarding, whenever a vendor submits a new W-9, and once before the filing season for any vendor paid a reportable amount that year. Re-verifying an already-matched pair every month adds cost without information.
Does a match mean the vendor is legitimate?
No. It means the name and TIN exist together in IRS records. Sanctions screening, address validation and beneficial-ownership checks answer different questions. See the sanctions guide.