Updated September 7, 2026. This guide covers the CP2000 in depth. For the other letters the IRS sends, see our plain-English guide to IRS notices.
The short answer: a CP2000 is not a bill and not an audit. It is the IRS telling you that income reported to it by a third party — an employer, a bank, a brokerage, a payment app — does not match what is on your return, and proposing a change to your tax. You have 30 days from the date on the notice to respond (60 days if you are outside the United States). You can agree, partly agree, or disagree, and you can do it online through the IRS Document Upload Tool. If you ignore it, the proposal becomes a Statutory Notice of Deficiency and then an assessment. Here is what the notice means, why it is often wrong, and exactly how to answer it.
What a CP2000 notice is
Every year the IRS runs its Automated Underreporter program: it matches the W-2s, 1099s, 1098s and other information returns filed under your Social Security number against the return you filed. When something reported to the IRS is missing from your return, or the amounts differ, the computer generates a CP2000. The IRS describes it as a proposal to adjust your income, payments, credits and/or deductions, and specifically says it is not an audit.
The notice lists each item the IRS thinks is unreported or mismatched, who reported it, the amount on your return versus the amount reported, and the proposed additional tax, penalty and interest. It also includes a Response form and, on current notices, an access code for the Document Upload Tool.
Why CP2000 notices are so often wrong, or partly wrong
The matching program compares gross amounts. It does not know what you paid for the stock you sold, that a 1099-K double-counted income you already reported as business revenue, or that a retirement distribution was rolled over. The most common false positives we see:
- Stock or crypto sales with no cost basis. The broker reports the gross proceeds on Form 1099-B. If the sale was left off the return, the IRS proposes tax on the full proceeds as if the cost was zero. Reporting the basis usually shrinks the change dramatically or turns it into a loss.
- 1099-K from a payment processor. Income received through Stripe, Square, PayPal or a marketplace was already included in Schedule C gross receipts, but the notice counts it again.
- Retirement rollovers and 1099-R codes. A rollover reported on a 1099-R was not taxable, but the return did not show it on the right line.
- A spouse’s or dependent’s form. A 1099 belonging to someone else on the return, or to a dependent who files separately, was matched to the wrong return.
- Corrected forms. The IRS matched an original 1099 that was later corrected by the issuer.
- Identity theft. Income reported under your SSN that you never received. This one needs an identity theft affidavit as well as a response.
Then there are the ones that are simply right: a forgotten 1099-NEC from a side job, interest from an account you closed, unemployment compensation. Agreeing to a correct notice is fine; what matters is not agreeing to an incorrect one.
How to respond: agree, partly agree, or disagree
The Response form on the notice gives you three positions, and the IRS says to respond even if you disagree. Do not file an amended return for the items in the notice; the IRS asks you to respond to the notice instead, because the CP2000 unit is already working the year.
If you agree. Check the agree box, sign the Response form (both spouses on a joint return), and return it. You can pay with the response or request a payment plan. Interest keeps running until the balance is paid, so paying what you can when you respond limits it.
If you partly agree. Check the disagree box, then explain which items are right and which are wrong, with documents for the ones you dispute. The IRS will recalculate.
If you disagree. Check the disagree box and attach a signed statement explaining why, with the supporting documents: the corrected 1099, the brokerage statement showing cost basis, the Schedule C showing the 1099-K income was already reported, the rollover confirmation, or whatever proves the point. Keep it factual and specific. A statement that works looks like this:
I disagree with the proposed change for the Form 1099-B proceeds of $18,400 from [Broker]. The shares sold had a cost basis of $17,900, shown on the enclosed brokerage statement. The correct gain is $500, not $18,400. I have enclosed a completed Form 8949 and Schedule D reflecting the sale. Please adjust the proposed amount accordingly.
If a third party made the mistake, the IRS suggests asking them to send you a corrected form and including it, or a written explanation, with your response.
Three ways to send your response
- Online: the IRS Document Upload Tool. Current CP2000 notices print an access code; you enter it, upload the signed Response form and your documents, and get a confirmation. This is the fastest route and the one we use.
- Fax: the fax number printed on the notice. Include the Response form as the first page.
- Mail: the address at the top of the notice. Send it tracked and keep a copy of everything.
If you cannot make the 30-day deadline, the IRS says to call the number on the notice and ask for more time. Do that before the deadline, not after.
What happens after you respond
The IRS reviews the response and either accepts it, sends a revised notice, or sends a letter asking for more. This routinely takes eight weeks or more. If you are still waiting and receive a second notice, respond to that one too, referencing the first. Do not assume silence means agreement.
What happens if you ignore a CP2000
If the IRS does not receive a response, or does not accept it, it may send another notice and then a CP3219A, Statutory Notice of Deficiency. That letter is different in kind: it gives you 90 days to petition the U.S. Tax Court if you disagree (150 days if addressed to you outside the United States), and that deadline cannot be extended. If you agree with the deficiency, you sign Form 5564 and return it. If you do nothing, the IRS assesses the tax and it goes to collection, with the failure-to-pay penalty and interest running, and with balance-due notices and eventually lien and levy letters following.
The CP2000 is the cheap moment to fix a mismatch. The CP3219A is the expensive one.
Penalties and interest on a CP2000
A CP2000 usually proposes interest from the original due date of the return. It may also propose the 20% accuracy-related penalty for a substantial understatement. If the understatement was caused by a reasonable mistake — a missing basis, a form you never received — the response can ask for the penalty to be removed on reasonable-cause grounds, and the IRS does remove it in appropriate cases. Interest itself is not removed, which is another reason to respond quickly.
If the notice is right and you cannot pay in full, respond and ask for a payment plan at the same time; the options are explained in our guide to IRS payment plans.
Should you amend your return?
Not for the items on the notice. The IRS specifically asks you to respond to the CP2000 rather than file Form 1040-X for those items, because the notice unit will make the adjustment. Amend only if you need to correct something else on the return that the notice did not raise — and mention it in your response so the two do not collide.
State follow-up
The IRS shares CP2000 results with state tax agencies. In California, the Franchise Tax Board typically issues its own notice adjusting your state return once the federal change is final. If you disagree with the federal notice, disagreeing early avoids a state bill built on a federal error; if you agree, expect the state notice and plan for it.
When to get help
Most single-item CP2000 notices — a forgotten 1099-INT, a small side-job payment — can be answered by the taxpayer. It is worth having someone represent you when the proposed change is large, when cost basis or business income has to be reconstructed, when the notice covers a year that also has other problems, or when a CP3219A has already arrived and the Tax Court clock is running. With a signed Form 2848 we can respond for you, speak to the IRS on your behalf, and handle the state follow-up. Our IRS resolution service is priced per matter and agreed before we start. If the year in question was never filed at all, start with unfiled tax returns instead — a substitute-for-return assessment is handled differently from a CP2000.
Common questions
Is a CP2000 an audit?
No. The IRS calls it a review of your return by mail, based on document matching. It is not an examination of your books and records.
How long do I have to respond?
30 days from the date on the notice, or 60 days if it was sent to an address outside the United States. Ask for more time by phone before the deadline if you need it.
Can I set up a payment plan for a CP2000 balance?
Yes. You can request one with your response, or apply online once the adjustment posts. Payment plans do not stop interest, but they stop the escalation.
What if I never got the 1099 the IRS is referring to?
Your wage & income transcript from the IRS shows every information return filed under your SSN. Pull it, confirm whether the income is real, and respond accordingly.
Do I have to respond if I agree?
Yes. Sign and return the Response form so the IRS can finalize the change, and pay or arrange payment. Not responding pushes the case toward a Notice of Deficiency even when you agree.
Received a CP2000 and not sure the numbers are right? Tell us what the notice says and we will tell you whether it is worth contesting before you sign anything.
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Questions about how this applies to your situation? We can talk it through and point you to the right next step.