Tax return under review: what the IRS is checking, how long it takes and what to do

What a tax return under review means

When your tax return is under review, a computer filter or an IRS employee has flagged something that needs a closer look before the refund can be released. The return has been received and posted, but the refund is frozen until the check is finished. You usually learn about it in one of three ways: a letter in the mail, a message in Where's My Refund, or a hold code on your account transcript.

Reviews are common. The National Taxpayer Advocate reported that more than 14 million individual returns were suspended during processing in the 2026 filing season. Being in that group does not mean you made a mistake. The IRS says plainly in its CP05 guidance that selection does not mean you were dishonest or made an error.

Why is my tax return under review? Common triggers

The IRS does not tell you exactly which filter caught your return, but its notices and the Taxpayer Advocate Service list the usual reasons.

Identity checks are a separate track with their own letters and steps. If your letter is a 5071C, start with the Letter 5071C guide rather than waiting, because nothing moves until you verify.

Tax return under review vs audit

A pre-refund review and an audit are handled by different parts of the IRS and have different stakes. A review confirms that the numbers on your return match what the IRS already has, then releases the refund, sometimes with a correction. An audit (examination) looks at whether you are entitled to deductions or income treatment and can produce a formal tax bill.

One practical clue: a CP05 or Letter 4464C says you do not need to take action if you filed the return. An audit letter asks you for documents or a meeting. On a transcript, a review often shows as a TC 570 hold, while a return sent to Examination shows a TC 420. See transaction code 570 for how the hold posts and later releases.

How long an IRS review of a tax refund takes

The wait depends on the kind of review. Income and withholding letters ask you to allow 60 days from the notice date before calling. The Taxpayer Advocate Service guideline range for reviews is 45 to 180 days, depending on complexity and how many issues are open.

Worked example: you e-file on February 20 and receive a CP05 dated March 16. The 60-day window runs to about May 15. If no refund or further letter has arrived by then, that is the point to call. Calling on April 1 will not speed things up, because the review is still inside its normal window.

How to respond to a review letter

1. Read the notice number in the top or bottom corner (CP05, 4464C, 5071C and so on). The number decides what you do next.
2. If it is an identity letter, verify as the letter directs. Nothing else happens until you do.
3. If it asks for documents, send copies (never originals) of the exact items listed, with the letter's response page on top, before the reply date.
4. If it says no action is needed, compare your return with your W-2s and 1099s. If you find a real error, the IRS Letter 4464C page suggests filing a corrected or amended return.
5. If you did not file the return at all, send Form 14039, Identity Theft Affidavit, as the CP05 and 4464C pages direct.
6. Mark the 60-day date on a calendar and check Where's My Refund once a day, not more.

When the review ends, one of three things happens: the refund is released as filed, it is released with a change explained in a notice such as a CP12, or the IRS writes asking for more. If the delay is causing a serious financial hardship, the Taxpayer Advocate Service may be able to help.