First and second B notices
A B notice is the letter a payer must send a payee after the IRS reports that a name and TIN pair on a filed information return did not match its records. There are two of them, they enclose different things, and only one can be cured with a fresh Form W-9.
The two notices and the two cures
- What starts it
- A CP2100 or CP2100A notice listing a payee whose name and TIN failed to match
- Mailing deadline
- 15 business days from the notice date or the date you received it, whichever is later
- Date on the notice
- No later than 30 business days after that same event
- First notice cure
- A signed Form W-9 with a matching name and TIN
- Second notice cure
- Validation from the SSA or the IRS. A fresh W-9 is disregarded
- Withholding starts
- No later than 30 business days after the CP2100 date or receipt, whichever is later
- Withholding stops
- No later than 30 calendar days after the cure reaches you
- Where the procedure lives
- Publication 1281, Parts 2 and 4
Where the notice comes from
You file information returns in January. Sometime later the IRS runs the name and TIN pairs on those returns against the SSA file of every Social Security number ever issued, the EIN name control file, and the ITIN and ATIN files. Pairs that do not match come back to you on a CP2100 or a CP2100A, with a listing of every account that failed. The IRS issues these twice a year, in October and the following April, so a client who has been quiet since spring will suddenly need a corrected form from you in the last week of October.
Which flavor arrives depends only on how many errors you made.
| Error documents on the listing | What you receive |
|---|---|
| 250 or more | A CP2100 with the listing on CD or DVD |
| 50 to 249 | A paper CP2100 |
| Fewer than 50 | A paper CP2100A |
Nothing on the notice tells you whether a given payee is on their first mismatch or their second. The regulations put that burden on you: the payer is responsible for tracking the status of every notice it receives. A company that files a few hundred 1099s and treats each CP2100 as a fresh event will eventually send a first B notice to someone who should have received a second, which cures nothing and leaves the withholding obligation unmet.
If you received a B notice rather than sent one, the thing you want is the cure and the deadline, and both are on the backup withholding page. Short version: first notice, send a corrected W-9; second notice, bring validation from the SSA or the IRS. Fix the underlying record first or you will mismatch again. Why pairs fail
A missing TIN is a different problem
The single most common procedural error is sending a B notice to a payee who never gave you a TIN at all. B notices exist for incorrect pairs. A missing TIN runs on the annual solicitation track instead, and the two have different deadlines, different documents and different penalty consequences.
| Missing TIN | Incorrect name and TIN pair | |
|---|---|---|
| Send a B notice? | No. Publication 1281 says not to | Yes, where the listing agrees with your records |
| What you do instead | Initial, first annual and second annual solicitations. The schedule | The B notice is the solicitation |
| When withholding starts | Immediately, on any reportable payment, and continues until a TIN arrives | No later than 30 business days after the CP2100 date or receipt |
| What ends it | Receipt of a TIN. Certification is required for some payment types | A signed W-9, or validation on a second notice |
| Annual solicitations still needed? | Yes, to avoid the penalty for filing without a TIN | The B notice satisfies the requirement for that year |
There are also situations where the listing names a payee and you send nothing at all. Work through the listing against your own records before you print a single envelope.
- The pair on the listing does not match what your records actually hold. You mistyped it on the return. Correct your records, use the right pair going forward, and send neither a B notice nor a correction to the IRS.
- The information changed after you filed. Same answer: update your records and move on.
- The IRS misprinted your data in processing. Note it and take no action.
- You already corrected the account. Listings run to a processing cutoff and may not reflect recent fixes, so a corrected account can still appear. Do not send a notice.
- The TIN was on file and you left it off the return by mistake. Do not contact the payee. Include it next time.
- No payments were made to the account and no return is required for it for a year. Publication 1281 does not require a notice in that case.
Where the relationship has ended, or the payment was a single transaction, the instinct is to skip the mailing. Publication 1281 says to send it anyway and try to get the correct TIN, then note your records so the account can be tracked for three years. You need that history if the vendor ever comes back.
The first B notice, step by step
Match the listing against your records
For an incorrect pair, you send a notice only where the name, TIN and account number on the listing agree with what you hold. Disagreement means the error is yours or the IRS system’s, and the actions above apply instead.
Fill in the notice before it goes out
The template in Publication 1281 arrives with blanks. The date, the account number, the current name and TIN on the account, the response deadline and the 24% withholding rate all have to be completed. A notice mailed with the rate line empty is not a notice.
Enclose a Form W-9
A copy of the current form or an acceptable substitute. An optional reply envelope is permitted and it measurably improves response rates. Substitute form rules
Mark the outer envelope
It must be clearly marked IMPORTANT TAX INFORMATION ENCLOSED or IMPORTANT TAX RETURN DOCUMENT ENCLOSED. This is not decoration. It is the reason the letter gets opened rather than binned with the marketing mail, and it is a stated requirement.
Mail it inside 15 business days
Counted from the date on the CP2100 or CP2100A, or the date you received it, whichever is later. Date the notice itself no later than 30 business days after that same event.
Update your records from what comes back
Put the corrected pair on future information returns. Do not send the signed Form W-9 to the IRS, and do not file a corrected information return unless you are also changing a dollar amount.
Publication 1281 states it twice: this information "may not be solicited by telephone." Calling the payee to warn them a letter is coming is fine and often helpful. The solicitation itself has to be the mailing, because the mailing is what you will produce if a penalty is ever proposed.
What each notice tells the payee
The two texts differ, and the difference is the whole point of the second notice. Both open with a warning and a deadline. Both state that a $50 penalty may apply for failing to furnish a correct pair. From there they diverge.
The second notice cure, precisely
This is where most write-ups go vague, and the detail matters because a payer who accepts the wrong document has not stopped its withholding obligation.
For an SSN, the payee sends a copy of the Social Security card. You may rely on that copy in only two situations. Either the name and SSN on the card differ from the pair printed on your second B notice, which tells you something genuinely new. Or the card shows a date of issuance no earlier than six months before the date of your notice, which tells you the SSA looked at this recently. A card issued in 1994 showing exactly the pair you already have is not validation of anything, and that is the trap. The payee has to go back to the SSA for a newly issued card.
| TIN type | Document that validates it |
|---|---|
| SSN | A copy of the Social Security card, subject to the two reliance conditions above |
| EIN | IRS Letter 147C, obtained by the payee from the service center where it files |
| ITIN | IRS Letter 685C, requested by the payee and forwarded to you |
| ATIN | IRS Letter 096C, requested by the payee and forwarded to you |
Every one of these routes requires the payee to attach a copy of your second B notice to the request and to the document they send back. Payees skip that step constantly, the SSA or IRS response arrives with no context, and the file sits unmatched while withholding continues. Say it twice in your cover note.
When withholding starts and when it stops
Four clocks run here and they are easy to conflate. The 15-business-day and 30-business-day windows on a first notice both count from the CP2100 event, so the second does not begin when the first ends. The second notice works differently: its withholding clock counts from the date of the notice you sent rather than from the CP2100.
| Situation | Start withholding | Stop withholding |
|---|---|---|
| First B notice, no response | No later than 30 business days after the CP2100 date or receipt, whichever is later. You may start the day after you receive the notice | No later than 30 calendar days after the signed Form W-9 arrives |
| Second B notice, no response | By the 30th business day after the date of your second B notice. You may start at any point in that window | No later than 30 days after the validation arrives |
| B notice returned undeliverable | Begin withholding. Try to find a correct address and remail | When a cure arrives at the corrected address |
| Missing TIN, no B notice sent | Immediately, on any reportable payment | On receipt of a TIN, certified where the payment type requires it |
Withheld amounts get deposited on your existing schedule and reported on Form 945, the annual return of withheld federal income tax, in addition to appearing in the federal income tax withheld box on the payee’s Form 1099. Missing the deposit is a separate penalty from missing the withholding. Payer penalty exposure
Tracking, third notices and undeliverable mail
The two-in-three-years rule is the reason all of this needs a system rather than a spreadsheet somebody maintains until they leave. Your first notification of an incorrect pair is the first time that payee TIN appears on a listing sent to you. The second notification is the second appearance of the same payee TIN within three calendar years. Nothing on the notice marks which is which, so the tracking is yours to build, and Publication 1281 asks you to hold the history for three years from the date of the first CP2100 or CP2100A.
- Two CP2100 notices in the same calendar year for one account do not require a second B notice. You may disregard the later one, even if it relates to a different tax year.
- Two notices in different calendar years that both relate to the same payee account for the same calendar year also do not require a second B notice.
- A third or subsequent notice can generally be ignored once you have completed both procedures and the name, TIN and account number are unchanged.
- The same payee appearing under a different name and TIN combination resets the cycle. Treat it as a first notification and enclose a W-9.
- An undeliverable B notice starts withholding, but keep the returned envelope. It runs on the same three-year tracking clock, and it is your evidence that the mailing happened.
- Generally you never send more than two B notices to the same account inside three calendar years.
Publication 1586 covers penalty relief for missing and incorrect name and TIN combinations, and the argument it contemplates is documentary. Dates, methods, copies of what you mailed, the returned envelopes, the validation documents you received. Assembled contemporaneously it is persuasive. Reconstructed in response to a proposed penalty notice, it reads as exactly that. Reasonable cause
What to do before any of this happens
Every B notice in your mailroom started with a pair that could have been checked for free before you filed. Run new vendors through the IRS TIN Matching program at onboarding and again in December, and the October CP2100 stops being an event. Two other habits do most of the remaining work: collect the W-9 before the first payment, and read Line 1 against Line 3a, because a disregarded single-member LLC reporting its own EIN is the most common substantive error a payer receives and it mismatches every single time.
Frequently asked questions
How long do I have to send a first B notice?
Fifteen business days from the date on the CP2100 or CP2100A notice, or the date you received it, whichever is later. Publication 1281 adds a second constraint that gets overlooked: the B notice itself must be dated no later than 30 business days after that same event, so you cannot backdate a late mailing.
Do I enclose a Form W-9 with a second B notice?
Publication 1281 says not to, and the reason is structural. After two notifications you are required to disregard any name and TIN combination the payee furnishes, even one certified under penalties of perjury, until the SSA or the IRS validates it. Enclosing a W-9 would invite a response you are not permitted to accept.
The payee returned a W-9 with the same incorrect number. Do I withhold?
Not on a first notification. Publication 1281 tells you to keep that Form W-9 on file to show the payee certified the combination, and not to backup withhold. The certification is what stops the withholding, even where the underlying record turns out to be wrong. The mismatch will surface again on a later CP2100, and that one is a second notification.
Can I telephone the payee instead of mailing the notice?
The procedure closes that off in one sentence: this information "may not be solicited by telephone." Call to warn someone a notice is coming if you like. The solicitation still has to go out on paper, in an envelope marked the way Publication 1281 specifies.
What happens on a third mismatch for the same payee?
Generally you may ignore it, provided you completed the first and second notice procedures and the name, TIN and account number are unchanged. One exception matters: if the listing shows the same payee under a different name and TIN combination, you treat that as a first notification and start the cycle over.
Does sending a B notice satisfy the annual solicitation requirement?
It does. Publication 1281 treats a B notice sent in response to a CP2100 or CP2100A as the annual solicitation for that year, so you do not send a second request on top of it. The annual solicitation schedule for a missing TIN is a separate track.
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