IRS NOTICE REFERENCE
Understanding your CP320B notice
You generally have two years from the date of the disallowance letter (for example, Letter 105-C) to file suit. Requesting an appeal does not extend this 2-year period. If you do not file suit within the 2-year period, o…
General information only. Not legal or tax advice.
Notice details
- Notice code
- CP320B
- Category
- Refund claims and litigation
- Severity tier
- Tier 4 — Escalation warranted. The notice involves collection enforcement, appeals rights, or significant penalty exposure.
- Governing law
- §6532; §7422; §6511 (Internal Revenue Code sections)
- Escalation flag
- This notice carries a forfeitable right, a hard statutory deadline, or criminal-preparer risk. It is flagged for escalation in the TaxRiskOS workflow.
- Source
- IRS.gov — Understanding Your IRS Notice
What this notice is
You generally have two years from the date of the disallowance letter (for example, Letter 105-C) to file suit. Requesting an appeal does not extend this 2-year period. If you do not file suit within the 2-year period, or do not enter into a written extension agreement before it expires the IRS cannot issue a refund or credit, even if Appeals later issues a favorable decision. Form 907, Agreement to Extend the Time to Bring Suit PDF , is a written agreement between a taxpayer and the Internal Revenue Service that extends the 2-year period for filing suit to seek a refund or credit after a claim disallowance. The agreement must be signed by both parties before the 2-year period expires . An executed agreement extends the time to file suit and will allow the IRS additional time to consider your claim disallowance and, if warranted, issue a refund or apply a credit.
Source: IRS.gov. Reproduced for reference. General information — not legal or tax advice.
What the IRS says to do
If you responded to a disallowance notice for your Employee Retention Credit and are awaiting a reply, and there are less than 6 months remaining in the 2-year period to file suit, you may request an extension of time to file suit using this process. You can protect your rights to bring suit or receive your refund or credit (if determined eligible) by following the steps detailed below: To request an extension: Download Form 907, Agreement to Extend the Time to Bring Suit PDF Complete the entire form and sign it. Submit your documents using the Document Upload Tool Wait for the IRS to review and return a countersigned copy of the agreement. The extension is not valid until the IRS signs it . If the 2-year deadline is quickly approaching, contact the phone number listed on your latest notice immediately.
This is the IRS’s own guidance reproduced from the IRS notice page. It describes the IRS’s process — it is not legal or tax advice from TaxRiskOS.
Governing IRS procedure (Internal Revenue Manual)
The IRS’s own internal procedures for handling this notice type are documented in the Internal Revenue Manual:
- IRM 4.10.11 — 4.10.11 Claims for Refund, Requests for Abatement, and Audit Reconsiderations
- IRM 4.19.16 — 4.19.16 Claims
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-cp320b-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.
Check this notice’s deadline (free tool)