The CP2000 Playbook: How to Respond Without Overpaying
What a CP2000 is, why most of them are wrong, the 30-day clock, and the step-by-step response that closes most of them to zero owed.
TL;DR
A CP2000 is a proposed adjustment, not a bill. The IRS matched information returns (1099s, W-2s, 1099-B) against your return and found a difference. Most differences are one of four things: missing basis on a brokerage sale, unreported retirement rollover, duplicated employer reporting, or timing mismatch. The response window is 30 days. A well-documented response resolves most notices to zero owed.
What a CP2000 actually is
A CP2000 is generated by the IRS Automated Underreporter (AUR) system when third-party information returns don't match what's on your Form 1040. It is not an audit. It is a proposed adjustment based on what the IRS can see. Most of what appears on the notice is mechanical — and most of it can be responded to with documentation rather than litigation.
The four most common causes
- Brokerage sales without reported basis. Pre-2011 holdings often lack broker-reported basis. The IRS sees the proceeds but not the cost, and defaults to treating the full proceeds as gain. Documentation of actual basis usually closes this.
- Retirement rollovers reported as distributions. A 1099-R with distribution code 1 or 7 can look like a taxable withdrawal when the full amount was actually rolled over within the 60-day window. Documentation of the receiving account and rollover date usually closes this.
- Duplicated employer reporting. Year-of-job-change W-2s can be reported in both state and federal numbers in ways that create apparent duplicates. A clean reconciliation usually closes this.
- Timing mismatches on 1099-NEC or 1099-MISC. Payer reports in one year, recipient recognized income in the year received. This requires either correcting the 1099 or showing the income was reported elsewhere.
Responding in 30 days
The response window on the notice is 30 days from the date printed on it — not 30 days from when you receive it. Start the clock immediately.
- Read the whole notice. The adjustment detail is usually in the middle pages, not the summary. Identify exactly which information returns triggered the adjustment.
- Pull transcripts. Account transcript and wage-and-income transcript show what the IRS actually has. Respond to what's on file, not what you remember.
- Draft a response letter. The notice includes a response form. Accept what is correct, dispute what is not, and attach supporting documentation for each dispute. Keep the tone factual.
- Mail certified, with tracking. Or fax to the number on the notice. Keep proof of delivery. The IRS fax method is generally the fastest and most reliable.
- If the adjustment stands, request Appeals. The notice will include a Form 5564 (Notice of Deficiency) if the adjustment is sustained. That opens a 90-day Tax Court window — but Appeals is almost always the better next step first.
What not to do
- Do not ignore it. If you do nothing, the IRS will issue a Statutory Notice of Deficiency and assess the full proposed adjustment.
- Do not just pay. A large share of CP2000s are fully resolvable. Paying without responding removes your leverage and your refund rights.
- Do not call the 800 number and agree. The phone representative can note your response but cannot unwind an assessment. Respond in writing.
- Do not use email. The IRS does not accept document submissions by email. Use mail or fax only.
If a CP2000 just arrived, you have 30 days. We take on CP2000 engagements flat-fee. Power of attorney filed the same day we engage.