Why do I keep getting CP2100 / B-Notices and how do I stop them?

CP2100 / “B-Notices” usually mean the IRS thinks the name and Taxpayer Identification Number (TIN) on your payee records don’t match, or that a TIN is missing/invalid. It’s basically the IRS telling you: “the W-9 info you have for this vendor/payee may be wrong.”

Why you keep getting them

Common causes:

• Wrong name/TIN combination on your records
  • Individual name vs. business name mismatch
  • SSN/ITIN/EIN entered incorrectly
• Missing or invalid TIN
• Old vendor records with outdated legal names, addresses, or entity type
• Backup withholding triggered because prior notices weren’t handled
• Formatting/data-entry issues
  • Extra spaces, punctuation, dashes, old DBA names, mixed personal/business names
• Your vendor onboarding process isn’t validating W-9s at entry, so bad records keep coming back every year

How to stop them

1) Fix your master vendor data

For each payee:

• Make sure the legal name exactly matches the TIN type
  • Individual/sole prop: person’s legal name on line 1; business name on line 2 if applicable
  • Corporation/partnership/LLC: name must match IRS registration
• Verify the TIN type is correct:
  • SSN/ITIN for individuals
  • EIN for entities
• Correct obvious typos and duplicate records

2) Get a new, correct W-9

Ask the vendor to complete a current Form W-9:

• Legal name
• Entity type
• TIN
• Address
• Certification/signature

3) Use IRS TIN matching before payments

If you’re a payer, enroll in the IRS TIN Matching program (or use a vendor/compliance provider) to catch mismatches before filing Forms 1099.

4) Respond to CP2100/B-Notice properly and on time

If you received one:

• First B-Notice: solicit a new W-9 and usually begin backup withholding if required
• Second B-Notice: you must get more formal proof (often a new W-9 plus IRS or SSA documentation, depending on the situation) before you can stop withholding treatment

5) Clean up your process

• Require W-9 collection at onboarding
• Validate TIN/name before first payment
• Review old vendors annually
• Standardize naming rules in your AP system
• Eliminate duplicate vendor profiles

Important timing

If you ignore CP2100/B-Notices, you may be required to:

• Start backup withholding on future reportable payments
• Potentially face IRS penalties for incorrect information returns

Best next steps

1. Pull the CP2100 list and identify each mismatched payee.
2. Contact each vendor for a fresh W-9.
3. Correct your records.
4. Set up TIN matching or a compliance check before filing 1099s.
5. Follow the IRS notice instructions exactly for first vs. second notices.

If you want, I can also give you:

• a CP2100/B-Notice response checklist
• a vendor W-9 cleanup process
• or a sample email to send vendors asking for a corrected W-9.