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A B Notice is not just another tax letter.
It usually means the IRS found a problem with a payee’s name or Taxpayer Identification Number, also called a TIN. This can happen when a business files an information return, such as a Form 1099, with a missing TIN, an obviously incorrect TIN, or a name/TIN combination that does not match IRS records.
The IRS may send a CP2100 or CP2100A notice to the payer. If you need a step-by-step response process, read our guide on the CP2100 and B Notice process. A CP2100 is generally issued when there are 50 or more incorrect information returns, while a CP2100A is used when there are fewer than 50. The instructions are generally the same; the difference is the number of incorrect returns listed.
This matters because a small vendor data issue can turn into a backup withholding problem if it is not handled properly.
What is a B Notice?
A B Notice is a backup withholding notice sent by the payer to the payee.
In simple terms, it tells the payee:
“The name or tax ID we have for you may not match IRS records. Please help us correct it.”
The IRS has two types of B Notices:
- First B Notice
- Second B Notice
They are not the same. The steps are different, and businesses should not treat both notices like a normal W-9 follow-up.
What is a First B Notice?
A First B Notice is usually the first formal notice connected to a name/TIN mismatch for a specific account.
For a First B Notice, the business generally sends the payee the First B Notice along with Form W-9. The payee is asked to complete and sign the W-9 with the correct legal name and TIN. This is also why businesses should know when to request a new W-9 instead of relying on old vendor records.
The goal is simple: correct the vendor record before the same issue appears again.
For example, a mismatch may happen because:
- the vendor used a DBA instead of the legal name
- the EIN or SSN was typed incorrectly
- the business name changed
- the W-9 on file is old
- the vendor record was entered manually with mistakes
This is why W-9 collection should happen before payment, not after year-end reporting starts.
What is a Second B Notice?
A Second B Notice is more serious.
It can happen when the same account appears again on a CP2100 or CP2100A notice within a three-calendar-year period. IRS Publication 1281 explains that the Second B Notice is different from the First B Notice and tells the payee to contact the IRS or SSA to obtain the correct name/TIN combination.
Here is the key point businesses should not miss:
For a Second B Notice, the business should not simply send another Form W-9.
IRS guidance says the Second B Notice should not include Form W-9. Instead, the payee may need to provide stronger validation, such as a copy of their Social Security card or an IRS Letter 147C verifying the correct name and EIN.
That is the big difference.
A First B Notice usually asks for a signed W-9.
A Second B Notice may require official validation from the SSA or IRS.
First B Notice vs Second B Notice: Simple comparison
| Topic | First B Notice | Second B Notice |
|---|---|---|
| When it happens | First CP2100/CP2100A listing for that account | Second listing within a three-calendar-year period |
| What the payer sends | First B Notice and Form W-9 | Second B Notice, but not Form W-9 |
| What the payee provides | Completed and signed W-9 | SSA or IRS validation, depending on the TIN type |
| Why it matters | Corrects the vendor record | Shows the mismatch may have repeated |
How quickly should businesses act?
Businesses should not ignore a CP2100 or CP2100A notice.
IRS Publication 1281 says payers generally have 15 business days from the date of the CP2100 or CP2100A notice, or the date they received it if later, to send the required B Notice.
Backup withholding may also apply. The IRS says backup withholding is currently 24% and may be required when a payee fails to provide a correct TIN.
That is why the process should be tracked carefully. This is not something teams should manage through scattered emails and spreadsheets.
Why these problems happen
Most B Notice issues start with basic vendor data problems.
Common examples include:
- legal name entered incorrectly
- DBA used instead of legal business name
- EIN or SSN entered with a typo
- missing W-9
- outdated W-9
- incomplete vendor record
- vendor information stored across different inboxes or spreadsheets
Some teams also use TIN matching before filing information returns to catch name/TIN issues earlier. The uncomfortable truth is simple: if your team collects W-9s manually, mistakes are easier to miss.
A vendor may send the form. Someone may save it in an email thread. Another person may enter the details into a spreadsheet. Later, the information may be used for 1099 filing without anyone checking whether the legal name and TIN were captured correctly.
That is how a small data issue becomes a compliance headache.
How better W-9 collection helps
A cleaner W-9 process helps businesses reduce avoidable name/TIN problems.
The goal is not just to “get the form.” The goal is to collect the right information, store it properly, and make it easy to find when needed.
A better process should include:
- requesting the W-9 before payment
- collecting the vendor’s legal name and TIN clearly
- keeping the completed W-9 in one place
- tracking submission history
- avoiding scattered email attachments
- reviewing vendor records before 1099 season
This gives accounting and AP teams a better chance of catching issues before they become IRS notices.
Frequently Asked Questions
What is the difference between a First B Notice and a Second B Notice?
A First B Notice is usually the first notice sent to a payee when the name or Taxpayer Identification Number on file does not match IRS records. The payee is generally asked to complete and sign Form W-9. A Second B Notice is more serious and may happen when the same account has another mismatch within a three-calendar-year period. For a Second B Notice, the payer should not simply send another Form W-9. The payee may need to provide IRS or SSA validation.
What causes a B Notice?
A B Notice is usually caused by a missing, incorrect, or mismatched Taxpayer Identification Number. Common causes include using a DBA instead of the legal name, typing the EIN or SSN incorrectly, using an outdated W-9, or filing a 1099 with incomplete vendor information.
Does a First B Notice require a new W-9?
In most cases, yes. For a First B Notice, the payee is generally asked to provide a completed and signed Form W-9 with the correct legal name and Taxpayer Identification Number.
Does a Second B Notice require another W-9?
No. A Second B Notice should not be handled by simply sending another Form W-9. IRS guidance says the Second B Notice should not include Form W-9. The payee may need to provide stronger verification, such as SSA or IRS validation of the correct name and TIN.
How quickly should a business respond to a CP2100 or CP2100A notice?
Businesses should act quickly after receiving a CP2100 or CP2100A notice. IRS guidance generally gives payers 15 business days from the notice date, or the date received if later, to send the required B Notice to the payee.
Simple takeaway
A First B Notice is usually the first warning that a payee’s name and TIN may not match IRS records.
A Second B Notice means the issue may have repeated. It is not handled the same way as the first notice. In many cases, another W-9 is not the right fix. The payee may need to provide IRS or SSA validation.
That is why W-9 collection should not be treated as a January cleanup task.
It should be part of vendor onboarding.
GetW9 helps businesses request, collect, and store completed W-9s in one place, so teams are not relying on scattered emails, spreadsheets, and manual follow-ups when vendor data matters most.
