IRS CP40 Notice
Your Account Was Assigned to a Private Collection Agency
A private firm will contact you about an IRS debt. This is the notice that tells you it is legitimate, and how to check.
What is CP40? CP40 tells you the IRS assigned your unpaid tax account balance to a private collection agency, and that the notice contains the name and contact information of that agency.
What This Notice Means
CP40 tells you the IRS assigned your unpaid tax account balance to a private collection agency, and that the notice contains the name and contact information of that agency.
The most useful thing on this page is the verification method, because a call from a private firm about an IRS debt is indistinguishable from a scam without it. The IRS states the agency will ask for your name and address of record, and will perform two-party verification using the Taxpayer Authentication number printed on your notice.
The IRS also states why this happens at all: it is required by law to contract with private collection agencies for certain unpaid tax accounts.
Why You Received This Notice
- 1The IRS states it assigned your unpaid tax account balance to a private collection agency.
- 2It states it is required by law to contract with private collection agencies to assist in the collection of certain unpaid tax accounts.
Important Deadline
The IRS publishes no number of days on the CP40 page.
What it does publish is a verification procedure, and the useful discipline is to complete that before discussing anything.
What You Should Do
- Work with the assigned private collection agency to resolve the unpaid account.
- Complete the two-party verification: the IRS states the agency will ask for your name and address of record, and will perform two-party verification using the Taxpayer Authentication number provided in your notice.
- Check the agency against the list. The IRS states the names of all private collection agencies under contract with it are on its private debt collection program page, and that the agency will also send a letter confirming assignment of your account.
- You can still pay the IRS directly. The IRS points to its payments page.
- The IRS points to Publication 4518, What You Can Expect When the IRS Assigns Your Account to a Private Collection Agency.
Resolution Options That May Help
What NOT to Do
- Do NOT give information to a caller who cannot complete the two-party verification using the Taxpayer Authentication number on your notice. That number is the check.
- Do NOT assume paying the agency is the only route. The IRS states you can pay it directly.
- Do NOT treat the assignment as the end of options. The IRS states the private collection agency will work with you to set up a payment plan if you cannot pay in full when contacted.
Frequently Asked Questions
How do I know the caller is really working for the IRS?
Why was my account transferred at all?
Can I pay over time?
Need Help With This Notice?
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Related Notices
Recommended Next Steps
- Find the Taxpayer Authentication number and the agency name on the notice.
- Check that name against the list on the IRS private debt collection program page before speaking to anyone.
- Read Publication 4518, which is the IRS publication written for exactly this situation.
Sources and last reviewed
- Understanding your CP40 notice — Internal Revenue Service, retrieved 2026-08-21
- Private debt collection — Internal Revenue Service, retrieved 2026-08-21
- Publication 4518, What You Can Expect When the IRS Assigns Your Account to a Private Collection Agency — Internal Revenue Service, retrieved 2026-08-21
Sourced to primary IRS materials and editorially reviewed on 2026-08-21. Not reviewed by a tax professional. Not tax advice. This page explains a notice in general terms and is not tax or legal advice about your situation. Always use the dates and instructions printed on the notice you actually received. Report a correction.