IRS · United States

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Form 3949-A: Information Referral (Report Suspected Tax Fraud)

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Quick answer

IRS Form 3949-A, Information Referral, is the form used to report a person or business you suspect of violating federal tax law — unreported income, false deductions, unfiled returns, or paying employees in cash off the books. You describe the alleged violation in Section B and mail the form to the IRS; providing your own details in Section C is optional, so you can report anonymously. With JustFill you upload the blank IRS Form 3949-A PDF, the AI auto-detects every field, you type or dictate your answers, and you download the completed form free.

Form
Form 3949-A
Issued by
IRS
Country
United States
Cost to fill
Free

What is Form 3949-A?

Suspect a business is paying workers under the table, or that someone is hiding income from the IRS? Form 3949-A, Information Referral, is how you report suspected violations of federal tax law by an individual or a business. Section A identifies who you are reporting, Section B describes the alleged violation — with checkboxes for common issues like unreported income, false deductions, failure to file, and failure to withhold tax — and Section C asks for your contact details, which you may leave blank to stay anonymous. It is not the right form for identity theft (that is Form 14039). JustFill makes the PDF fillable in your browser: the AI auto-detects every field and checkbox, you type or dictate your report, and you download it free.

Who fills out Form 3949-A?

  • Employees or ex-employees who know a business is paying wages in cash without withholding or reporting
  • Anyone aware of a person or business hiding income, claiming false deductions or exemptions, or not filing required returns
  • Contractors, vendors, or competitors who have firsthand knowledge of falsified books or altered documents
  • Former spouses or business partners reporting unreported income they have direct knowledge of
  • People who want to alert the IRS anonymously without becoming a formal whistleblower claimant

Field-by-field breakdown

What each section of Form 3949-A asks for. JustFill’s AI will detect these fields automatically when you upload the PDF — review the breakdown below so you know what to enter.

Section A1 — Individual being reported

Name, address, SSN (if known), date of birth, occupation, and marital status of the person you are reporting.

Section A2 — Business being reported

Business name, address, EIN (if known), and a description of what the business does.

Section B, line 3 — Alleged violation

Checkboxes for the type of violation: unreported income, false exemptions or deductions, failure to file, failure to withhold or pay tax, kickbacks, false documents, and more.

Section B, line 4 — Unreported income and years

The tax years involved and your estimate of the unreported income for each year.

Section B, line 5 — Comments

A factual description of the violation: who, what, when, how you know, and where records or funds are located.

Section B, lines 6–8 — Records and safety

Whether books or records are available, whether you consider the person dangerous, and banks or financial institutions they use.

Section C — Your information (optional)

Your name, address, and phone. You may leave this blank to report anonymously.

Common mistakes to avoid

  • 1Using Form 3949-A for identity theft — if someone used your SSN to file a return or get a job, file Form 14039, Identity Theft Affidavit, instead.
  • 2Being vague — reports with specific facts, tax years, dollar estimates, and how you know are far more actionable than general accusations. Use line 5 to give concrete details.
  • 3Expecting a status update — federal law keeps tax matters confidential, so the IRS will not tell you whether it acted on your referral or what happened to the person you reported.

How JustFill helps you complete Form 3949-A

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Frequently asked questions

Yes. Form 3949-A is issued by the IRS and is free to download and complete. JustFill provides a free fillable interface — there is no charge to complete the form.
Download the current blank Form 3949-A PDF directly from the IRS at irs.gov/forms-pubs/about-form-3949-a — it is free. Then upload that PDF into JustFill to complete it online without printing.
Yes. Section C, which asks for your name and contact information, is optional. The IRS accepts anonymous referrals, though providing contact details lets them follow up if they need clarification. The IRS keeps the identity of informants confidential either way.
No. Form 3949-A is an information referral only. If you want to claim a whistleblower award for reporting significant tax underpayments, that is a separate process filed with the IRS Whistleblower Office on Form 211.
Print the completed form and mail it to the IRS at the address shown in the form instructions. The IRS does not accept this referral by phone, and you will not receive confirmation or updates after submitting it.

Official source: Form 3949-A on IRS’s website

JustFill is an independent product and is not affiliated with, endorsed by, or sponsored by IRS or any government agency. Always verify your completed form on the official version before signing or submitting.