IRS Notice CP2100 / CP2100A: What It Means and What to Do
The CP2100 and CP2100A are sent to payers, such as businesses and financial institutions, that filed information returns like Forms 1099 with missing or mismatched payee names and TINs. The notice lists the affected payees and tells you that you may need to send them a "B" notice and start backup withholding. The CP2100 goes to payers with 50 or more returns with errors; the CP2100A goes to those with fewer than 50. The instructions are the same.
CP2100 key facts
| Official name | CP2100 / CP2100A: the payee's name and taxpayer identification number (TIN) on your information return is missing or doesn't match our records (backup withholding notice to payers) |
|---|---|
| Who gets it | Businesses |
| Severity | 3 of 5: Moderate: respond by the deadline The payer must act within set business-day deadlines to meet backup withholding rules and avoid penalties, but no enforcement has started. |
| Response window | Send the "B" notice to the payee within 15 business days from the date of the CP2100/CP2100A or the date you received it, whichever is later. Begin backup withholding no later than 30 business days after you received the notice if the payee doesn't respond, and stop within 30 calendar days after you receive the certified TIN or validation (Publication 1281). |
| Deadline basis | Counted from the date printed on the notice. |
Severity is RAHA Financials' own 1 to 5 rating of how urgent the notice usually is. It is not an IRS classification.
How long do I have to respond to a CP2100?
15 business days from the notice date. Enter the date printed on your CP2100 to see your respond-by date.
The date printed on your notice always controls. Open CP2100 in the IRS Notice Decoder.
Why did I get a CP2100?
Common reasons include:
- A payee's TIN was left off a Form 1099 or other information return
- The TIN was obviously wrong (for example, not nine digits or containing letters)
- The payee's name and TIN combination doesn't match IRS or SSA records
- The payee changed their name, or a typo was made when collecting or entering the TIN
What should I do?
- Compare the list of payees on the notice with your own records.
- For missing or obviously incorrect TINs, begin backup withholding right away if you haven't already, and make the required annual requests for the TIN.
- For mismatched TINs that agree with your records, send the payee the correct "B" notice within 15 business days from the notice date or when you received it, whichever is later. For a first notice, include Form W-9. For a second notice within three calendar years, don't include Form W-9; the payee must get validation from SSA or the IRS.
- If the listed information doesn't agree with your records because of your own error or a later change, just correct your records for future returns; don't send a B notice or write to the IRS.
- If the payee doesn't respond, begin backup withholding at the current rate of 24% no later than 30 business days after you received the notice.
- Report and deposit backup withholding on Form 945, and stop withholding within 30 calendar days after you receive a certified TIN or validation.
- Keep records of each notice and B notice, since you must track whether a payee is on a first or second notice within three calendar years.
What documents do I need?
- The CP2100 or CP2100A and its list of payees
- Your payee account records and the information returns as filed
- Signed Forms W-9 on file
- Copies of B notices sent and payee responses (Form W-9, Social Security card copy, or IRS Letter 147C)
- Publication 1281 for the B notice text and procedures
- Form 945 and backup withholding deposit records
What should I avoid?
- Don't ask payees for their TIN by phone; Publication 1281 says it may not be solicited by telephone.
- Don't send corrected information returns only to fix the TIN, and don't send signed Forms W-9 to the IRS.
- Don't miss the 15-business-day window to mail the B notice, or the 30-business-day deadline to begin backup withholding.
- Don't send a first or second B notice for missing TINs; begin backup withholding and make annual solicitations instead.
What if I disagree with a CP2100?
If an account on the list doesn't match your records because of a recent SSA update, your own filing error or an IRS processing error, the IRS says to correct or update your records as needed. You don't have to call or write to the IRS. If you don't recognize the Transmitter Control Code (TCC) on the notice, contact any third party that filed returns for you. If you later receive a proposed information return penalty, Publication 1586 explains how to show reasonable cause, which generally depends on having made the required solicitations.
What happens if I ignore a CP2100?
Payers that don't send required B notices or begin backup withholding may become liable for the amounts that should have been withheld. They may also face penalties for filing information returns with missing or incorrect TINs. Payees may also be charged a penalty for failing to provide a correct TIN.
What else should I know about CP2100?
The CP2100 is about the payer's obligations, not the payer's own tax. It starts precise business-day clocks under the backup withholding "B" program. The first-versus-second notice distinction matters. A first B notice goes out with Form W-9, and a signed W-9 lets you stop withholding. A second listing within three calendar years requires a different B notice with no W-9, and you may stop only after the payee sends SSA or IRS validation (a Social Security card copy or IRS Letter 147C for an EIN). Many listed mismatches come from the payer's own records, such as typos or name changes. For those, Publication 1281 says to just correct your records and send no B notice. Using the IRS TIN Matching program before filing can reduce future listings.
Want a professional to handle your CP2100 response?
IRS Notice Response Plan
Fixed price, quoted before any work startsFixed fee.
- Review of your notice and account transcript
- A written plan: agree, partly agree, or dispute
- Draft response and list of supporting documents
- Deadline tracking so nothing lapses
CP2100: frequently asked questions
What's the difference between a CP2100 and a CP2100A?
Only volume. The IRS issues a CP2100 if you filed 50 or more information returns with errors and a CP2100A if you filed fewer than 50. The information and instructions are the same.
When does the IRS send these notices?
Twice a year, in October and the following April.
When do I start and stop backup withholding?
For mismatched TINs, begin no later than 30 business days after you receive the notice if the payee hasn't provided a certified TIN. Stop within 30 calendar days after you receive it (or SSA or IRS validation for a second notice). For missing or obviously incorrect TINs, withhold immediately.
Does the notice say whether it's a first or second notice for a payee?
No. Publication 1281 says payers are responsible for tracking whether a payee has been listed before within three calendar years.
Do I have to tell the IRS I fixed a payee's TIN?
No. Update your records, use the corrected information on future returns, and stop backup withholding as required. You don't need to contact the IRS.
