How to fax an IRS CP2000 response, underreporter notice reply
Fax your CP2000 response to the IRS using the fax number printed on the CP2000 notice itself (upper right corner of page 1). Respond within the 30-day window to avoid automatic assessment. Faxing provides instant proof of timely response.
CP2000 (Notice of Proposed Adjustment) is the IRS's underreporter notice. The IRS sends it when amounts on your tax return don't match third-party records like:
W-2 wages reported by your employer
1099 income reported by clients/banks
Capital gains reported by brokerages
Mortgage interest reported by lenders
Social Security benefits reported by SSA
CP2000 proposes additional tax, interest, and sometimes penalties. It is not an audit, it's an automated cross-match. But ignoring CP2000 leads to formal assessment.
The 30-day response deadline
CP2000 gives you 30 days from the notice date to respond. The 30 days starts from the date printed at the top of the notice, not the date you received it.
⚠️ If you ignore CP2000: The IRS will issue a Statutory Notice of Deficiency (Letter 3219) which gives you 90 days to petition Tax Court. If you ignore that too, the IRS assesses the tax and starts collection.
Agree, partially agree, or disagree
CP2000 includes a response form with three options:
Agree (Box 1): Sign the agreement, pay the proposed amount, done.
Disagree (Box 2): Explain why the IRS is wrong with documentation. Most common scenarios: the income was already reported elsewhere, the 1099 was issued in error, or you have offsetting deductions.
Partially agree (Box 3): Agree with some changes but not others. Specify which.
Respond before the 30 days run out
Upload your CP2000 response, we fax to the number on your notice and provide instant transmission proof.
The fax number for your CP2000 response is printed on your CP2000 notice itself, in the upper right corner of page 1. Different CP2000 notices route to different IRS service centers, you must use the number on your specific notice.
How long do I have to respond to CP2000?
You have 30 days from the date printed on the CP2000 notice to respond. The deadline is hard, if you miss it, the IRS issues a Statutory Notice of Deficiency, which starts a 90-day clock to petition Tax Court.
What happens if I ignore CP2000?
If you don't respond within 30 days, the IRS issues a Statutory Notice of Deficiency (Letter 3219). If you ignore that too, the IRS assesses the proposed tax, interest, and penalties, and begins collection actions including liens and levies.
Is CP2000 an audit?
No. CP2000 is an automated underreporter notice, the IRS computer cross-matched your return against third-party reports (W-2, 1099, etc.) and found a discrepancy. It's a proposed adjustment, not a formal audit. However, if you don't respond, it can become an assessment.
Should I pay CP2000 or dispute it?
Read the proposed changes carefully. If the IRS is correct (you forgot to report income), agree and pay. If you have documentation showing the IRS is wrong, dispute. About 50% of CP2000 disputes result in some adjustment in the taxpayer's favor.
What documents should I include with my CP2000 response?
Send: the signed response form (page 7-8 of CP2000), a detailed explanation letter for each disputed item, copies of supporting documents (W-2s, 1099s, brokerage statements, receipts), and a cover sheet referencing the CP2000 notice number.
Can my CPA respond to CP2000 on my behalf?
Yes. File Form 2848 (Power of Attorney) authorizing your CPA, then they can sign and submit the CP2000 response on your behalf. Many disputed CP2000s benefit from CPA involvement.
How long does the IRS take to process CP2000 responses?
Typical processing is 60-90 days. Complex cases with significant supporting documentation can take 6+ months. You may receive a Letter 4314 requesting more information during review, this restarts the clock.
Can I get an extension on the 30-day CP2000 deadline?
The 30-day window is generally fixed, but you can fax a request for additional time to the same number on your CP2000 notice. The IRS may grant 30 extra days if you can show you need time to gather documentation.
What is a CP2000 versus a CP2501?
CP2501 is the IRS's first letter for underreporter cases, it asks you to clarify or provide more info before issuing a formal proposed adjustment. CP2000 is the formal proposed adjustment that follows if CP2501 isn't resolved or wasn't sent.
Do I need to amend my tax return after CP2000?
Generally no. The CP2000 process is the IRS's way of correcting your return without requiring an amendment. If you agree with the changes, your tax record is updated automatically. Don't file Form 1040-X for CP2000 issues unless instructed.
Can I fax CP2000 response with an electronic signature?
Yes. The IRS accepts electronic signatures on CP2000 response forms as of 2021. Sign electronically, save as PDF, and fax via Faxend or another online fax service.
Don't let CP2000 become an audit
Upload your CP2000 response form. We fax to the number on your notice and confirm transmission within seconds. Pay $2.99.