IRS NOTICE REFERENCE
Understanding your CP2100 or CP2100A Notice
The payee's name and taxpayer identification number (TIN) on your information return is missing or doesn’t match our records. You may need to begin backup withholding on these payee accounts if you haven't already done s…
General information only. Not legal or tax advice.
Notice details
- Notice code
- CP2100-OR-CP2100A
- Category
- Penalty
- Severity tier
- Tier 2 — Action or response expected. The IRS has taken or proposed an action and expects a response or payment.
- Governing law
- §6721; §6722; §6751 (Internal Revenue Code sections)
- Source
- IRS.gov — Understanding Your IRS Notice
What this notice is
The payee's name and taxpayer identification number (TIN) on your information return is missing or doesn’t match our records. You may need to begin backup withholding on these payee accounts if you haven't already done so. You should begin backup withholding immediately if the payee refuses or fails to provide a TIN, or if the TIN provided is obviously incorrect (not 9 digits or contains something other than a number). The CP2100 and 2100A notice includes a list of missing, incorrect, or not currently issued payee TINs.
Source: IRS.gov. Reproduced for reference. General information — not legal or tax advice.
Governing IRS procedure (Internal Revenue Manual)
The IRS’s own internal procedures for handling this notice type are documented in the Internal Revenue Manual:
Reference to published IRS procedure. General information — not legal or tax advice.
Official IRS reference
Read the official notice page on IRS.gov: https://www.irs.gov/individuals/understanding-your-cp2100-or-cp2100a-notice
Related tools
TaxRiskOS is workflow software for practitioners — it captures the notice, computes the deadline, surfaces the escalation tier, and builds a document checklist. It documents process; it does not give advice or draft responses.
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