IRS TIN Matching Result Codes: What Each One Means and What to Do Next

The Complete Result Code Reference

Code	IRS Description	What It Means
0	Match	TIN and name match IRS records - you're clear to file
1	TIN missing or not 9-digit numeric	TIN is blank, too short/long, or contains non-numeric characters
2	TIN not currently issued	The TIN is correctly formatted but not assigned to any taxpayer
3	TIN/name combination does not match	TIN exists but is registered to a different name
4	Invalid request	The record is malformed — a file format error, not a data error
5	Duplicate request	This TIN/name combination was already submitted in this session
6	Matched on SSN	TIN type was unknown; match found in the SSN database - you're clear to file
7	Matched on EIN	TIN type was unknown; match found in the EIN database - you're clear to file
8	Matched on both SSN and EIN	TIN type was unknown; match found in both databases - you're clear to file

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Code 0: Match

The TIN and name combination you submitted matches IRS records. The IRS will not flag this return as a mismatch.

What to do: Nothing — this vendor is validated for filing. Record the result date as part of your compliance documentation.

One thing to know: Code 0 is accurate as of the date you run the match. If a vendor updates their legal name or EIN between your pre-filing validation and when the IRS processes your 1099, a mismatch can still appear on a subsequent CP2100. Running TIN matching close to your filing deadline minimizes — but doesn't fully eliminate — this gap. If you ever receive a CP2100 for a vendor that previously returned Code 0, the match date in your records strengthens a reasonable cause argument.

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Code 1: TIN Missing or Not 9-Digit Numeric

The TIN field in your submission was blank, contained fewer or more than 9 digits, or included non-numeric characters.

Most common causes:

• Vendor never provided a TIN — the field is empty in your vendor master
• Leading zero stripped during Excel export (a TIN starting with 0 became 8 digits when exported as a number column)
• TIN formatted with hyphens (e.g., 12-3456789 instead of 123456789)
• Partial TIN entered — someone keyed 8 digits instead of 9

What to do:

1. Check whether the TIN field is simply blank. If so, you don't have a TIN on file — request a W-9 before filing.
2. If a TIN is present, check the format: strip hyphens, spaces, and any non-numeric characters. Verify the digit count.
3. If the TIN came from an Excel export, check whether leading zeros were dropped. Reformat the column as text and re-export.
4. Fix and resubmit. Code 1 is almost always a formatting problem you control, not a vendor data problem.

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Code 2: TIN Not Currently Issued

The TIN is correctly formatted (9 digits, numeric) but the IRS has no record of it being assigned to any taxpayer.

What it likely means:

• The vendor provided a TIN they made up or misremembered
• A digit was transposed during data entry (e.g., 123456789 entered as 132456789)
• The vendor is a foreign entity that provided an ITIN that has expired or was never issued
• In rare cases, a very recently assigned EIN that hasn't fully propagated in IRS systems

What to do:

1. Request a new W-9 from the vendor. Ask them to confirm their TIN from their EIN assignment letter (for businesses) or their Social Security card or prior-year tax return (for individuals).
2. If the vendor is a business, use EIN lookup by company name to cross-reference — you may be able to identify the correct EIN from public records even if the vendor provided a wrong one.
3. Do not file with a Code 2 TIN. Filing an information return with an unissued TIN will not generate a CP2100 (because there's no matching record to flag against), but it can trigger a Code 1 or Code 2 penalty under Section 6721 for incorrect TIN.
4. If the vendor is unresponsive, begin backup withholding at 24% and document your solicitation attempts. Code 2 on its own is not the same as receiving a B-Notice, but your documentation of the issue matters if a penalty is later proposed.

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Code 3: TIN/Name Combination Does Not Match

This is the most common non-match result in bulk TIN validation. The TIN itself exists in IRS records — but it's associated with a different name than what you submitted.

What it likely means:

• The vendor provided the correct TIN but your records have a name variation that doesn't match their IRS filing name
• The vendor is a sole proprietor who gave you their DBA instead of their legal name
• A business name change hasn't been updated in IRS records yet
• Single-member LLC: you have the LLC name, but the TIN is registered to the owner's name
• A minor typo, abbreviation, or truncation creates a name control mismatch

What to do:

1. Before requesting a new W-9, try name variations first. The IRS name control is derived from the first four significant characters of the name. Try the vendor's full legal name, the owner's personal name if it's a sole proprietorship, and the name without any DBA or trade name.
2. If you can't resolve the mismatch by name variation, request a corrected W-9. Ask the vendor to use the exact legal name that appears on their most recent federal tax return or EIN assignment letter.
3. For businesses, EIN lookup by company name can surface the legal name the IRS has on file, which you can then use to reconcile against what the vendor provided.
4. Document your correction efforts. If the vendor is unresponsive after two W-9 solicitation attempts, begin backup withholding at 24%.

Code 3 is not always a vendor error. A significant portion of Code 3 results come from how your own system stores the name — abbreviations, DBA usage, truncation on import. Check your records before escalating to the vendor.

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Code 4: Invalid Request

The record itself was malformed — the IRS system couldn't parse the input. This is a file preparation error, not a data error.

Most common causes:

• Wrong delimiter (using commas or tabs instead of semicolons in a bulk file)
• Extra or missing fields in the record
• Disallowed characters in the name field (apostrophes, commas, periods)
• Name field exceeds 40 characters
• TIN type field contains something other than 1, 2, or 3

What to do:

Code 4 means fix the file format, not the vendor data. Review the record's structure against the IRS bulk file format requirements:

• Semicolons as delimiters
• TIN type: 1 (EIN), 2 (SSN), or 3 (unknown)
• TIN: 9 digits, numeric only
• Name: 40 characters max, letters/numbers/spaces/hyphens/ampersands only
• No header row

If you're getting Code 4 on many records at once, the issue is almost certainly a global formatting problem — wrong delimiter or a disallowed character appearing throughout your name field. Fix the export or conversion process and resubmit.

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Code 5: Duplicate Request

The IRS will not process a TIN/name combination that was already submitted in the same session or recently by the same payer.

What to do: Nothing — if this vendor already returned Code 0 in your current run, you don't need a second result. Code 5 appears when your file contains the same TIN/name combination more than once, or when you've re-submitted a vendor from a prior session.

The lockout risk — and why it matters most at filing deadlines.

The IRS TIN Matching system has a built-in security mechanism that detects when the same payer EIN is used to research the same TIN under different names. If this pattern is detected, access is blocked for 96 hours. No exceptions, no early release — the lockout runs its full course regardless of your circumstances.

This is designed to prevent bad actors from probing the IRS database to find which name is associated with a given TIN. The problem is that it also catches legitimate AP teams who are trying to resolve a Code 3 mismatch by testing name variations — a completely reasonable thing to do, but one that triggers the same detection pattern.

The timing makes it worse. Lockouts happen most often in late January and early March, when teams are under pressure to validate large vendor lists before the 1099-NEC and 1099-MISC filing deadlines. An AP manager working through a stack of Code 3 results at 9pm on January 30th, trying name variations to resolve mismatches before the next morning's deadline, can lock their entire organization out of IRS e-Services until February 3rd — after the 1099-NEC deadline has passed.

We've seen this scenario play out more times than we can count. It's one of the most stressful situations an AP team can face, and it's entirely avoidable.

How TIN Comply prevents this from happening to you: TIN Comply's processing doesn't route through IRS e-Services directly. Your TIN matching runs through TIN Comply's system, which handles duplicate detection, name variation testing, and EIN discovery automatically — without any risk of triggering a lockout on your IRS account. If you're already locked out and have a deadline in the next 96 hours, TIN Comply can run your full vendor list right now. Your IRS lockout status has no effect on TIN Comply's matching.

Don't test name variations manually through the IRS portal to resolve Code 3 results. Use EIN lookup or request a corrected W-9 — and let TIN Comply handle the matching.

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Codes 6, 7, and 8: Matched on Unknown TIN Type

These codes only appear when you submitted a record with TIN type 3 (unknown). They indicate a successful match but tell you which database the match came from.

Code	Database Matched	What It Tells You
6	SSN database	The TIN is registered as a Social Security Number — vendor is likely an individual
7	EIN database	The TIN is registered as an Employer Identification Number — vendor is likely a business entity
8	Both SSN and EIN	The same TIN/name combination appears in both databases

These are match results — but pay attention to what they reveal.

If you submitted a TIN type of 3 and received Code 6, the TIN matched as an SSN. That tells you the vendor is an individual (or a sole proprietor using their SSN). Depending on your vendor master and how you track entity types, you may want to update the record to TIN type 2 for future submissions.

If you received Code 7, the TIN matched as an EIN — a business entity. Update your record to TIN type 1.

Code 8 is less common and typically occurs when a sole proprietor has an EIN that was issued under the same name control as their SSN. It's a valid match in both systems.

When Code 6, 7, or 8 can still be a problem: Entity type mismatches affect which 1099 form applies and whether backup withholding rules differ. If your system has been treating a vendor as a corporation (and therefore exempt from 1099 reporting) but they return Code 6 as an individual, you may have a reporting gap. Use these codes to audit and correct entity type classifications in your vendor master — not just to confirm a match.

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Summary: What to Do by Code

Code	Priority	Next Step
0	Done	Document result date; file as normal
1	Fix format	Check TIN format; strip hyphens/spaces; verify digit count; request W-9 if blank
2	Request W-9	Vendor TIN doesn't exist; request corrected W-9; consider EIN lookup
3	Investigate first	Try name variations; if unresolved, request corrected W-9
4	Fix file format	Formatting error in your submission — fix delimiter, characters, or field structure
5	Already done	This vendor was already validated in this session
6	Match (SSN)	Update entity type to individual (TIN type 2) in vendor master
7	Match (EIN)	Update entity type to business (TIN type 1) in vendor master
8	Match (both)	Sole proprietor with EIN; valid match in both systems

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How TIN Comply Can Help

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Frequently Asked Questions

Can I get a Code 0 result and still receive a CP2100 notice? Yes. Code 0 reflects the match at the time of your validation. If the vendor's information changes between your pre-filing TIN match and when the IRS processes your return, a mismatch can still appear. Document your match date — it's evidence of due diligence if you need to respond to a 972CG.

What's the difference between Code 2 and Code 3? Code 2 means the TIN doesn't exist — it's not assigned to anyone. Code 3 means the TIN exists and is assigned, just to a different name. Code 2 is more serious and usually indicates a wrong or fabricated TIN. Code 3 is often a name formatting issue that a corrected W-9 resolves.

Should I begin backup withholding for Code 2 and Code 3 results? Not immediately. The B-Notice and backup withholding process is triggered by IRS notification (CP2100), not by your own TIN matching results. However, if a vendor is unresponsive to your W-9 request after a Code 2 or Code 3 result, documenting your solicitation attempts and beginning withholding voluntarily is a defensible compliance posture — especially if the same vendor later appears on a CP2100.

Why did I get Code 4 on every record in my bulk file? Almost certainly a delimiter error. If you exported a CSV and submitted it without converting to semicolon-delimited format, every record will return Code 4. Fix the delimiter and resubmit. See the IRS bulk file format guide for exact requirements.

What does it mean if a vendor returns Code 3 every year even after providing a corrected W-9? Persistent Code 3 results after W-9 correction usually mean one of three things: the vendor's EIN is registered under a different legal name than what appears on their W-9, the name hasn't been updated with the IRS after a business name change, or the vendor has multiple EINs and is providing the wrong one. Use EIN lookup by company name to cross-reference the legal name in IRS records directly.

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This article is for informational purposes only and does not constitute legal or tax advice. Consult a qualified professional for guidance specific to your organization.