IRS Data Study
CP2000 Underreporter Statistics: The IRS Document-Matching Machine (2026)
Headline figure: in fiscal year 2025 the IRS received about 4.47 billion information returns (W-2s, 1099s, and similar documents). Its Automated Underreporter program — the system behind the CP2000 notice — closed about 987,460 cases and assessed roughly $5.9 billion in additional tax and interest. These CP2000 underreporter statistics come from the IRS Data Book, Table 3-8.
Holding a CP2000 right now?
Send us a photo of it. An experienced tax professional will compare the IRS's numbers against your records and explain your options — free, confidential, no pressure. No one can promise a specific outcome, but you deserve to know exactly where you stand before the response date passes.
If you searched for CP2000 underreporter statistics, you are probably holding a notice that says the IRS thinks you left income off your return. Take a breath. A CP2000 is a computer-generated proposal, not a full audit. Below are the verified FY2025 numbers, what each figure means in plain English, and the source so you — or any reporter or researcher — can cite it.
Key findings: CP2000 underreporter statistics for FY2025
- The IRS received about 4.47 billion information returns in fiscal year 2025 — the W-2s, 1099s, and similar documents employers and payers file directly with the agency.
- The Automated Underreporter (AUR) program, which matches those documents to filed tax returns and produces CP2000 notices, closed about 987,460 cases in FY2025.
- The AUR program assessed about $5.9 billion in additional tax and interest in FY2025.
- A separate program, the Automated Substitute for Return (ASFR) — used when someone does not file at all — closed about 592,773 cases and assessed about $2.9 billion in FY2025.
- A CP2000 is a document-match proposal, not an audit. It proposes a change you can agree with, partly agree with, or dispute with your own records.
The numbers in one table
| Metric (Fiscal Year 2025) | Figure |
|---|---|
| Information returns received by the IRS | ~4.47 billion |
| Automated Underreporter (CP2000) cases closed | ~987,460 |
| Automated Underreporter additional tax & interest assessed | ~$5.9 billion |
| Automated Substitute for Return cases closed | ~592,773 |
| Automated Substitute for Return additional tax assessed | ~$2.9 billion |
Source: IRS Data Book FY2025, Table 3-8 (Information Reporting Program). Figures rounded.
What this means in plain English
Think of the 4.47 billion information returns as the IRS's master copy of your income. Every time an employer pays you, a bank pays interest, a brokerage reports a stock sale, or a platform sends you a 1099, a copy goes to the IRS. A computer then lines those documents up against what you reported on your tax return.
When the numbers don't match, the AUR system flags the gap and generates a CP2000 notice — short for the proposed-change letter that says, in effect, "our records show more income than your return; here is what we think you now owe." That is how the program closed nearly a million cases and assessed about $5.9 billion in a single year. The machine does the matching; a notice goes out automatically.
Here is the part that matters most: a CP2000 is a proposal. It is not a final bill, and it is not an audit of your whole return. The IRS is often missing context — a cost basis you can prove, income reported under a spouse's number, or a 1099 that double-counted a payment. You have the right to respond by the date on the notice and show your side. If you do nothing, the IRS generally assesses the full proposed amount and the case moves toward collection.
The Automated Substitute for Return numbers tell a related story. When someone never files a return at all, the IRS can build one for them using only those information returns — with no deductions, credits, or filing-status benefits in your favor. That program closed about 592,773 cases and assessed about $2.9 billion in FY2025. The lesson in both data sets is the same: the IRS already has the documents, and silence is the worst response.
How to read and respond to a CP2000
- Find the response date. It's printed near the top. That date — usually about 30 days out — is your window to agree or disagree.
- Compare the income line by line. The notice lists each document the IRS matched. Check each one against your own W-2s, 1099s, and records.
- Decide if it's right, partly right, or wrong. The IRS often only sees gross amounts. A stock sale showing $20,000 in proceeds may have had $18,000 in cost basis — meaning your real gain was small, not the full amount proposed.
- Respond either way. Sign and return the agreement form if it's correct, or send a written explanation with copies of your documents if it isn't. Keep copies of everything.
- If you already missed the date, you may still be able to fix an incorrect assessment through audit reconsideration or by amending — an experienced tax professional can tell you which path fits your facts.
Methodology & source
All figures on this page come from the IRS Data Book, Fiscal Year 2025, Table 3-8 (Information Reporting Program), published by the IRS Statistics of Income division. The "information returns received" count reflects documents such as W-2s and 1099s filed with the IRS during the fiscal year. "Cases closed" and "additional tax and interest assessed" reflect the Automated Underreporter (AUR) and Automated Substitute for Return (ASFR) program activity reported in that table. We rounded the dollar figures and case counts for readability and did not adjust, project, or combine them with any other data set. Figures describe federal fiscal year 2025 and are not comparable across years without consulting the same table for each year.
Cite this study
Suggested attribution: Clarity Tax Relief, "CP2000 Underreporter Statistics: The IRS Document-Matching Machine (2026)," analysis of IRS Data Book FY2025, Table 3-8. Available at CP2000 Underreporter Statistics: The IRS Document-Matching Machine (2026).
Journalists and researchers are welcome to reference these figures with a link back to this page. For the underlying data, see the IRS Data Book source linked in the Methodology section above.
CP2000 underreporter questions, answered
Is a CP2000 the same as an audit?
No. A CP2000 is a proposed change generated by a computer match between your tax return and the information returns (W-2s and 1099s) that third parties sent the IRS. It is not a formal audit. You can agree, partly agree, or disagree and respond with your own documentation.
How many CP2000 notices does the IRS send each year?
The IRS does not publish a single CP2000 mailing count, but its Automated Underreporter program — the system that produces CP2000 notices — closed about 987,460 cases in fiscal year 2025, according to the IRS Data Book. Each closed case generally began with a proposed-change notice.
How much extra tax does the IRS assess through the underreporter program?
In fiscal year 2025 the Automated Underreporter program assessed about $5.9 billion in additional tax and interest, based on the IRS Data Book, Table 3-8. A separate program, the Automated Substitute for Return, assessed about $2.9 billion that same year.
What should I do if I get a CP2000?
Read it carefully and compare the income listed against your own records before you do anything. If the IRS is right, you can agree and arrange to pay. If it is wrong or incomplete, you respond by the date on the notice with documentation showing the correct figures. Do not ignore it — silence usually leads to the IRS assessing the full proposed amount.
This guide is general information, not tax or legal advice for your specific situation. Eligibility for IRS programs depends on individual facts and circumstances; no outcome is guaranteed.