IRS CP2000 Notice: Should I Agree, Disagree, or Partially Respond?

A CP2000 is not an audit. It is not a bill. It is a proposed adjustment from the IRS’s Automated Underreporter (AUR) program, which matches the income reported on your return against the information returns filed by third parties (W-2s, 1099s, 1042-S forms, K-1s). When the numbers do not match, the computer generates a CP2000 notice showing the discrepancy, the proposed additional tax, and any proposed penalties and interest. The IRS sends roughly 4 million CP2000 notices per year. A significant portion of them are wrong, either because the IRS did not account for offsetting deductions, or because the income was already reported on a different line, or because the information return itself was incorrect. You have 30 days to respond (sometimes 60, as stated on the notice), and how you respond determines whether this becomes a small correction or a large and unnecessary tax bill.

What triggered the CP2000?

The AUR system compares two things: the income your return reports and the income that third parties reported to the IRS under your Social Security number or ITIN. When those numbers differ, the system generates the notice. Common triggers:

A 1099-NEC, 1099-MISC, or 1099-K that you received but did not include on your return, or included on a different schedule than the IRS expected. A W-2 from a short-term employer you forgot about. A 1099-B for stock sales where your return reported a different basis or gain. A 1099-R for a retirement distribution that you rolled over (and reported as non-taxable) but the IRS flagged as taxable. A K-1 from a partnership or S corporation where the income category on the K-1 does not align with where you reported it. A 1042-S for income subject to treaty benefits that the IRS’s system did not match to your treaty claim.

The last scenario is especially common for cross-border filers. If a Canadian resident receives US-source dividends or interest with tax withheld under the treaty rate, the payer files a 1042-S. The IRS’s matching system sometimes treats the gross amount as unreported income because the AUR system does not always match 1042-S data to treaty claims on Form 1040-NR or to foreign tax credit claims on Form 1116. The result is a CP2000 proposing tax on income that was either treaty-exempt or already reflected on the return.

Should I agree, disagree, or partially respond?

Read the notice line by line before deciding. The CP2000 lists each discrepancy with the information return source, the amount reported by the third party, and the amount reported on your return. For each item:

Agree if the income was genuinely unreported and you owe the tax. This happens. People forget about a 1099-INT from a bank they closed, or a 1099-DIV from a brokerage that generated a small dividend. If the income is real and was not on your return, the fastest resolution is to agree, pay the proposed tax (or set up a payment plan), and move on. The IRS will add interest from the original due date. If the resulting understatement is large enough to trigger the accuracy penalty (20% under IRC 6662), you may be able to get the penalty abated separately using first-time abatement or reasonable cause.

Disagree if the income was already reported (on a different line or schedule), if the information return is wrong, if you have offsetting deductions or basis, or if the income is treaty-exempt. Common reasons to disagree:

• You reported the income on a different schedule (for example, the IRS shows a 1099-NEC not on Schedule C, but you reported it on Schedule E as rental management income).
• The 1099 is incorrect (wrong amount, wrong person, duplicate reporting). In this case, ask the issuer to correct the 1099 first, but respond to the CP2000 within the deadline regardless.
• You have basis in the asset. A 1099-B shows $50,000 in stock sales, but your basis was $48,000, so the gain was only $2,000. The AUR system sometimes does not match basis if it was not reported on the 1099-B.
• The income is exempt under a tax treaty. A 1042-S shows $10,000 in US-source income, but the treaty reduces the tax to zero or to a rate lower than the AUR system assumed.
• You rolled over a retirement distribution. A 1099-R shows a $40,000 distribution, but you rolled it into another IRA within 60 days. The rollover was reported on your return, but the AUR system flagged it anyway.

Partially agree if some items on the notice are correct and others are not. This is the most common situation on multi-item CP2000s. You can agree to the items the IRS got right and contest the rest. Respond in writing, item by item, stating which you agree with, which you disagree with, and why.

How do I write the response?

The CP2000 notice includes a response form. You can use it or write a letter. Either way, include:

1. Your name, SSN, and the notice number (printed on the CP2000).
2. The tax year in question.
3. For each item you disagree with: the specific item, why the IRS’s proposed change is incorrect, and supporting documentation.

Attach copies of the documents that support your position: the corrected 1099, the brokerage statement showing basis, the rollover confirmation, the treaty claim supporting the 1042-S treatment, the Schedule C or E that reported the income on a different line. Label each document with the line item it relates to.

Mail the response to the address on the notice, or fax it to the number provided. The IRS also accepts responses through its online account system for some notices. Do not call to resolve a CP2000; the phone representatives cannot adjudicate the discrepancy.

What happens if I do not respond?

If you do not respond within the deadline (printed on the notice, usually 30 or 60 days), the IRS will assess the full proposed amount as a statutory notice of deficiency (sometimes called a “90-day letter”). At that point, the proposed adjustment becomes an actual assessment with penalties and interest. You then have 90 days to petition the US Tax Court if you disagree, or the assessment becomes final and the IRS begins collection.

The transition from CP2000 (proposed, no legal force) to statutory notice of deficiency (legal force, Tax Court clock starts) is the critical boundary. Responding to the CP2000 keeps the matter in the AUR unit, which is generally easier and faster to resolve than a deficiency proceeding. Missing the deadline does not mean you lose the right to contest the adjustment, but it moves the dispute into a more formal and slower process.

What about the proposed penalties?

Most CP2000 notices include a proposed accuracy-related penalty of 20% under IRC 6662 if the understatement exceeds $5,000 or 10% of the correct tax. If you successfully contest the underlying income adjustment, the penalty goes away with it. If you agree to part of the adjustment but the remaining understatement drops below the penalty threshold, the penalty should also be removed.

If the penalty stands (because you did owe additional tax and the understatement was substantial), you can request abatement separately. First-time abatement works if you had a clean compliance history. Reasonable cause works if the understatement was due to reliance on a tax professional, a good-faith treaty interpretation, or another circumstance beyond your control.

Interest is not abatable in most circumstances. It runs from the original due date of the return, not from the date of the CP2000 notice.

What are the cross-border traps?

For US citizens and green card holders living in Canada, and for Canadian residents with US-source income, CP2000 notices have several recurring failure modes:

1042-S mismatches. The AUR system does not reliably match 1042-S forms to treaty claims. If you received US-source dividends or interest with treaty-rate withholding, the system may treat the gross amount as unreported income. The fix: respond with the 1042-S, the treaty article, and the Form 1116 or 1040-NR schedule showing how the income was reported.

RRSP and TFSA distributions. If a Canadian financial institution issued a 1099-R or information return for an RRSP or TFSA distribution, the AUR system may flag it. RRSP distributions are generally taxable in the US (unless the treaty election under Article XVIII(7) was made before 2008). TFSA distributions are taxable in the US because the TFSA is not a qualified plan under US law. If the income was reported on the return but classified differently than the AUR system expected, explain the classification.

Foreign tax credits. The AUR system does not always account for foreign tax credits. If the proposed adjustment adds income but does not give credit for Canadian tax already paid on that income, the proposed tax is overstated. Respond with Form 1116 and proof of Canadian tax paid.

Stock options from Canadian employers. If you exercised stock options from a Canadian employer while holding a green card, the income may appear on both a T4 (Canadian) and a W-2 or 1099 (US), or on neither, depending on the employer’s reporting. The AUR system may flag the discrepancy. The treaty’s Article XV governs employment income, and the sourcing of stock option income depends on the exercise date and the location of employment.

What if the IRS does not accept my response?

The AUR unit will either accept your response (and adjust or withdraw the proposed changes) or reject it (and issue a revised notice or a statutory notice of deficiency). If the AUR unit rejects your response and you still disagree, you have two options:

First, request reconsideration within the AUR unit. Call the number on the response letter, explain the remaining disagreement, and ask for a supervisor review. Second, if the IRS issues a statutory notice of deficiency, you have 90 days to file a petition with the US Tax Court (IRC 6213). The Tax Court can hear the case under its small case procedure if the amount is under $50,000.

For cross-border filers who receive a deficiency notice while living in Canada, the 90-day deadline is extended to 150 days if the notice is addressed to a person outside the United States (IRC 6213(a)). This extension is automatic; you do not need to request it. For response templates covering the five most common correspondence audit scenarios (including cross-border income mismatches), see IRS correspondence audit response templates.

How does this affect my Canadian return?

If the CP2000 results in additional US tax (because you agree to some or all of the adjustment), the additional US tax may generate a foreign tax credit on your Canadian return under Article XXIV of the Canada-US treaty. You would amend the Canadian return for the corresponding year to claim the additional credit, assuming the Canadian statute of limitations is still open (normally three years from the original assessment under ITA 152(3.1)).

If the CP2000 results in a reduction of US tax (because the IRS agrees the income was overstated or the credits were understated), and you already claimed a Canadian foreign tax credit for the original US tax, the Canadian credit was overstated. Technically, the CRA could reassess the Canadian return to recapture the excess credit, though this is rare unless the amounts are material and the CRA receives the information through the treaty’s exchange provisions.

Either way, keep a copy of the final CP2000 resolution (the IRS letter confirming the adjustment) with your Canadian tax records. If the CRA ever reviews your foreign tax credit claim, this is the supporting document.

What should I do next?

Read the CP2000 line by line. For each proposed adjustment, determine whether the income was already reported (on a different line), whether the information return is wrong, whether you have offsetting basis or deductions, or whether the income is treaty-exempt. Respond in writing before the deadline. Attach supporting documents for every item you contest. If you agree to some items and disagree with others, respond partially.

If you are a cross-border filer and the CP2000 involves 1042-S income, treaty claims, or foreign tax credits, the response needs to address the treaty and credit issues specifically. A generic “I disagree” will not resolve a treaty mismatch.

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.