Quick summary

When the IRS flags a tax return for identity verification it’s usually to stop suspected identity theft or to confirm mismatched information. The agency will send a notice (commonly Letter 5071C) with clear next steps: use the IRS online Identity Verification Service, call the number on the notice, or submit documents by mail. If you suspect identity theft, you may need to file Form 14039, Identity Theft Affidavit. (See IRS guidance: If you receive Letter 5071C and Form 14039 pages on IRS.gov.)

Below I walk through the options, exact documents the IRS accepts, a step-by-step checklist, timelines, common mistakes I see in practice, and where to turn if the issue doesn’t resolve.

Why the IRS flags returns (briefly)

  • Suspicious or duplicate Social Security numbers on multiple returns.
  • Filing patterns that match known fraud signatures (very large refunds, unusual credits).
  • Mismatched personal data (name, SSN, prior-year AGI) compared with IRS records.
  • You recently changed your name or address and the IRS records haven’t been updated.

These flags are preventive. In my practice I’ve seen honest filers delayed because records weren’t synchronized; treating the notice promptly typically fixes the problem.

Four ways to prove your identity to the IRS

1) Online verification (fastest when it works)

  • What to use: IRS Online Identity Verification (Secure Access/ID Verify) available at the link provided on your IRS notice. This tool lets you verify identity using personal data and document images in many cases. (IRS Identity Verification Service guidance.)
  • What you’ll need: a smartphone or computer with a camera, your Social Security number, one or two specific financial or tax data points (prior year AGI or a tax return PIN), and a government photo ID for some cases.
  • Benefits: often immediate confirmation and fastest refund release.
  • Caveats: Secure Access can be strict—if you’ve never set it up or have mismatched credit-report data, phone or mail options may be necessary.

2) Phone verification

  • How it works: The notice will include an IRS phone number to call. An IRS representative will ask verification questions and may require follow-up documentation.
  • Tips: Call from a quiet place, have your notice and supporting documents handy, and note the representative’s name/ID and the time of the call.
  • Limitation: phone lines can be busy during peak season—expect hold times.

3) Mail-in documents

  • What to send: copies (never originals) of acceptable documents: government-issued photo ID (driver’s license or passport), Social Security card (or SSA letter), previous-year tax return transcript or a signed copy of last year’s Form 1040, W-2s or 1099s, and proof of address (utility bill, bank statement).
  • How to submit: follow the mailing address and instructions on your notice exactly. Use tracked, overnight, or certified mail; add a cover note with your notice ID and contact info. Clearly label documents and avoid sending unnecessary originals.
  • Processing time: mailed documents require manual review and often take several weeks to process.

4) Filing Form 14039 (Identity Theft Affidavit)

  • When to use it: if you believe your identity has been used to file a fraudulent return in your name, complete Form 14039 (Identity Theft Affidavit) per IRS instructions: https://www.irs.gov/forms-pubs/about-form-14039.
  • Next steps: the IRS will flag your account for identity theft and may assign an Identity Protection PIN (IP PIN) or other protective measures.
  • Note: submitting Form 14039 starts a separate identity-theft resolution process that can take months to fully resolve.

What documents the IRS typically accepts

  • Government-issued photo ID (driver’s license, state ID, passport).
  • Social Security card or a SSA benefit or earnings statement.
  • Prior-year tax return (signed copy) or tax return transcript from IRS.[1]
  • W-2s, 1099s, or other documents showing earned income and withholding.
  • Bank account statements showing direct deposit information (if refund issues relate to deposit).
  • Proof of name change (marriage certificate, court order) if name mismatch is the reason.

Good practice: submit clear, legible copies. Write your tax year and notice ID on each page.

Step-by-step checklist (practical)

  1. Read the IRS notice carefully and confirm it’s legitimate (Letter 5071C or similarly titled). The IRS will not initiate identity verification with threatening language or requests for payment.
  2. Choose your verification method: online (fastest), phone, or mail. If you suspect fraud, include Form 14039.
  3. Collect documents: photo ID, prior-year return, W-2/1099, SSA documentation, proof of address, and any notice pages.
  4. If mailing, make copies only—do not send originals. Use tracked mail and keep receipts.
  5. If phoning, document the rep’s name and reference numbers. Ask for expected processing times.
  6. Follow up if you don’t receive confirmation within the stated time frame on the notice.
  7. If you still have problems after 30–45 days, consider contacting the Taxpayer Advocate Service (TAS) or a tax professional.

Timelines and what to expect

  • Online verification: often immediate or within a few days for follow-up.
  • Phone verification: can be same-day to several days depending on workload.
  • Mail-in document review: typically several weeks; during peak season it may be longer.
  • Identity-theft investigations: these can take months because the IRS must investigate and coordinate with other agencies.

In practice I advise clients to assume mail submissions will take 4–8 weeks and identity-theft tracks can be longer. If a refund is urgent, use tracked mail or start with online verification.

Common mistakes I see

  • Sending originals. The IRS requests copies; originals may be lost in processing.
  • Ignoring the notice. This freezes processing and delays refunds.
  • Submitting incomplete documentation (e.g., a photo ID without linking proof of Social Security number).
  • Using public Wi‑Fi for online verification—use a secure, private connection.

If you suspect identity theft

  • File Form 14039 with the IRS (see: About Form 14039 on IRS.gov).
  • Visit IdentityTheft.gov (FTC) to report identity theft and get a personalized recovery plan. (FTC identity-theft resource.)
  • Consider requesting an IRS Identity Protection PIN (IP PIN) at the IRS Get an IP PIN page. An IP PIN prevents others from filing using your SSN but getting one may require additional verification steps.
  • Place a fraud alert or credit freeze with the three major credit bureaus.

For a deeper look at preventing and recovering from tax-related identity theft, see our related guides: why your refund may be held for identity verification (internal) and navigating IRS Identity Protection PINs (IP PIN) (internal). Also see identity-theft recovery steps for credit file repair.

When to escalate: Taxpayer Advocate Service and professional help

If you’ve followed IRS instructions and waited the reasonable times cited in your notice but still have no resolution, contact the Taxpayer Advocate Service (TAS) (independent across IRS) or consult a qualified tax professional or attorney. TAS assists taxpayers whose problems persist and can intervene when the IRS’s normal systems are not resolving cases. (See taxpayeradvocate.irs.gov.)

In my practice, TAS is particularly helpful when a client’s refund has been delayed more than 60–90 days due to identity verification and standard channels aren’t producing updates.

Security and privacy best practices

  • Share documents only through the channel specified on the IRS notice. If you’re unsure, call the IRS number on the notice to confirm.
  • Use tracked/certified mail when mailing documents and never email sensitive documents to generic addresses.
  • Consider scanning documents and wiping metadata if you upload photos—make sure images are clear and not blurry.

Frequently asked questions (concise answers)

  • What if I never received a notice but the IRS flagged my return? The IRS usually sends a notice to the last known address or the email you provided through an authorized e-file provider. If you think your mailing address is out of date, contact the IRS or your tax professional.
  • Can I call the IRS general number? Use the phone number on your notice first; it routes you to the correct unit.
  • Will I lose my refund if I don’t respond? Your refund will be delayed; if you ignore the notice, the IRS will stop processing until you verify.

Professional disclaimer

This article is educational and does not substitute for personalized tax or legal advice. For complex identity-theft situations or significant financial impact, consult a qualified tax professional, attorney, or the Taxpayer Advocate Service.

Authoritative sources

  • IRS — If you receive Letter 5071C and Identity Verification pages (IRS.gov)
  • IRS — About Form 14039, Identity Theft Affidavit (irs.gov/forms-pubs/about-form-14039)
  • FTC — IdentityTheft.gov recovery tools and guidance (FTC.gov)
  • Taxpayer Advocate Service — taxpayeradvocate.irs.gov

If you’d like, I can also draft a printable checklist you can mail with your documents or a sample cover letter you can include with a Form 14039 submission.