IRS Integrity and Verification Operations is the IRS unit that screens filed returns for fraud, identity theft, and errors before any refund is paid. If your return has been pulled by this unit, your refund is frozen while the agency verifies one specific thing: a credit you claimed, the income or withholding you reported, or that you are the person who actually filed the return. You will not get a letter labeled “IVO.” You will get a numbered notice, and what you do next depends entirely on which notice arrived.
How an IVO Review Is Different From an Audit
A traditional IRS examination can reach across your whole return and ask for books, records, and financial documents in several areas. An IVO review is narrow by design. It targets one line item, one credit, or the filer’s identity, and it happens before your refund is released rather than after.
Shortly after you file, the IRS runs your return through automated data-matching systems that compare what you reported against information already on file from employers, banks, and schools. When a figure does not match or a pattern looks statistically unusual, the system pulls your return for a human reviewer. The pre-refund timing matters because refundable credits like the Earned Income Tax Credit and the Additional Child Tax Credit can pay out more than the filer owes in tax, so an erroneous claim moves real money out of the Treasury rather than just shrinking a bill. The EITC alone had an estimated improper payment rate of roughly 33 percent of total program payments in fiscal year 2023.1Tax Policy Center. What Are Error Rates for Refundable Credits and What Causes Them?
Why Returns Get Flagged
IVO reviews are not random. Returns are pulled when specific risk patterns show up in the automated screens.
- Data mismatches. Wages, interest, or other income on your return does not line up with what employers or financial institutions reported on Forms W-2 and 1099. Even small gaps trigger alerts.
- Refundable credit eligibility. This is the most common trigger. Claiming the EITC, the Additional Child Tax Credit, or the American Opportunity Tax Credit when the underlying data does not support the claim, such as an education credit with no corresponding Form 1098-T from a school, or a dependent who does not appear to meet the residency test.
- Identity concerns. Multiple returns filed under the same Social Security number, an unusual filing pattern given your history, or return data that does not match what the IRS has on file for you.2Internal Revenue Service. What Taxpayers Should Do if They Get an Identity Theft Letter From the IRS
- Head of household status. Filing as head of household without documentation showing you paid more than half the cost of maintaining the home. The IRS checks this closely because the status carries a larger standard deduction and more favorable brackets.
The Notices IVO Sends
Your response depends on which notice you got. The CP05 family handles income, withholding, and credit verification. The letters in the 5071C, 4883C, and 5747C series handle identity.
CP05: Wait, Do Nothing
A CP05 tells you the IRS needs more time to verify your income, withholding, or tax credits. It does not ask you to do anything. You do not need to call or send documents. The IRS tells you to wait at least 60 days before reaching out.3Internal Revenue Service. Understanding Your CP05 Notice If the review clears internally, your refund is released without further action from you.
CP05A: Send Documents
If the IRS cannot resolve the issue on its own, it escalates to a CP05A, which does require a response. The notice asks for documents proving your income and federal withholding by a specific deadline. Acceptable documents include copies of at least three pay stubs (including your year-end stub), a letter on company letterhead from your employer, or a statement of retirement benefits. After you submit, allow another 60 days for the review.4Internal Revenue Service. Understanding Your CP05A Notice
Identity Verification Letters
When the IRS suspects someone may have filed using your Social Security number, it sends one of three letters, each with its own response method.5Taxpayer Advocate Service. Identity Verification and Your Tax Return
- Letter 5071C. The most widely issued identity letter. You can verify online through the IRS identity verification portal using an ID.me account, or by phone.6Internal Revenue Service. Verify Your Return
- Letter 4883C. Requires you to call the Taxpayer Protection Program hotline listed on the letter. Have the letter, the return in question, a prior-year return if available, and all supporting W-2s and 1099s on hand before you call.7Internal Revenue Service. Understanding Your Letter 4883C
- Letter 5747C. Requires an in-person appointment at a Taxpayer Assistance Center. You must appear physically even if you have an authorized representative, and you need a valid government-issued photo ID plus your supporting tax documents.8Internal Revenue Service. Understanding Your Letter 5747C
The IRS will not process your return or release your refund until identity verification is complete. If you cannot find your letter, check your IRS online account or call the Taxpayer Protection Program line at 800-830-5084.
What to Send and How to Send It
When a notice does ask for documentation, the quality of your first response controls how long you wait. Incomplete or illegible packages trigger another round of correspondence and can easily add 60 or more days.
For income and withholding, the IRS wants primary source documents, not your return itself. Send at least three pay stubs including the final year-end stub, and make sure each shows the date wages were earned, gross income, and federal tax withheld. A letter on employer letterhead also works. Do not resend your W-2; the IRS already has that data and is looking for independent confirmation.4Internal Revenue Service. Understanding Your CP05A Notice
For dependents, head of household status, or EITC eligibility, you need to prove both the qualifying relationship and shared residency. The IRS accepts school records, medical records, and daycare statements that show the child’s name and your address. A letter on official letterhead from a school, doctor’s office, or social service agency showing names, a shared address, and dates works as well. Lease agreements or mortgage statements help establish the address.9Internal Revenue Service. Form 14824 – Supporting Documents to Prove Filing Status
Assemble everything with a cover sheet referencing the notice number and your Social Security number. Keep originals and send clear copies. Follow the notice’s instructions exactly, including the specific IVO mailing address or fax number. Use certified mail with a return receipt; that receipt is your proof of timely response if the IRS later says the package never arrived.
How Long It Takes and the PATH Act Hold
After you submit documents, expect roughly 60 days for the IRS to finish the review. Peak filing season and complex documentation push that out further. If you have heard nothing after 60 days, call the number on your original notice.
If you claimed the EITC or Additional Child Tax Credit, your refund is also subject to a mandatory hold under the Protecting Americans from Tax Hikes (PATH) Act, independent of any IVO review. By law, the IRS cannot issue these refunds before mid-February.10Internal Revenue Service. When to Expect Your Refund if You Claimed the Earned Income Tax Credit or Additional Child Tax Credit An IVO review stacked on top of a PATH Act hold can push the timeline out by months.
Long holds come with one benefit. Federal law requires the IRS to pay interest on refunds not issued within 45 days after the filing deadline, or within 45 days of filing if you filed late.11Office of the Law Revision Counsel. 26 USC 6611 – Interest on Overpayments The rate is set quarterly; it was 7 percent for the first quarter of 2026 and 6 percent for the second. The IRS is supposed to add this automatically when it releases your refund, but check the amount against your original return to confirm interest was included.
What Happens If You Do Nothing
Ignoring an IVO notice is expensive. For identity letters, the IRS simply will not process the return or release the refund. There is no workaround. For credit and income notices, the IRS will disallow the credits or deductions in question, which shrinks your refund or creates a balance due.12Internal Revenue Service. Understanding Your IRS Notice or Letter
If the IRS confirms a discrepancy after disallowing a credit, it may issue a Notice of Deficiency, sometimes called a 90-day letter. You then have 90 days from the date on the notice (150 days if you live outside the country) to file a petition with the U.S. Tax Court if you disagree.13Internal Revenue Service. Understanding Your CP3219N Notice Miss that window and the IRS assesses the tax; your options narrow sharply. You can also try to resolve the dispute before court by filing a written protest with the IRS Independent Office of Appeals within the time limit on your notice, generally 30 days.14Internal Revenue Service. Preparing a Request for Appeals
A disallowance can also carry penalties. If the IRS finds you underreported income or claimed credits negligently, you may owe an accuracy-related penalty of 20 percent of the resulting underpayment.15Internal Revenue Service. Accuracy-Related Penalty The longer-term consequence is a credit ban. If the IRS determines a claim of the EITC, Child Tax Credit, or American Opportunity Tax Credit was due to reckless or intentional disregard of the rules, you are barred from claiming that credit for two years. If the claim was fraudulent, the ban runs ten years.16Office of the Law Revision Counsel. 26 USC 32 – Earned Income
When to Bring in the Taxpayer Advocate
Most IVO reviews finish within a few months. Some stall, with the IRS sending interim letters every 60 days asking for more time without actually resolving anything. If a delayed refund is causing real financial hardship, the Taxpayer Advocate Service (TAS) can step in.
TAS takes cases when a taxpayer is facing economic harm, an immediate threat of adverse action, or when an IRS process has failed to resolve an issue within normal timeframes. A tax problem unresolved for more than 30 days past normal processing time, or an IRS failure to respond by a date it promised, qualifies as a systemic burden case TAS can accept.17Taxpayer Advocate Service. Submit a Request for Assistance To request help, file Form 911 with your local TAS office. Explain which IVO notice you received, when you responded, what the IRS has done since, and how the delay is harming you financially. TAS assistance is free, and the service can order the IRS to expedite your case when circumstances warrant.