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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 identify the person or business in Section A, describe the alleged violation in Section B, and either submit it online through the IRS Form 3949-A Information Referral tool or print and mail it to Internal Revenue Service, PO Box 3801, Ogden, UT 84409 — there is no fax number and the IRS does not take referrals by phone. Section C (your own details) is optional, so you can report anonymously, and the IRS keeps your identity confidential either way. The current PDF is Form 3949-A (Rev. October 2020), free from irs.gov. With JustFill you upload that blank, the AI auto-detects every field and checkbox, you type or dictate your answers, and the first clean completed PDF download is included at no charge.

Form
Form 3949-A
Issued by
IRS
Country
United States
Free allowance
First clean download
Official edition
Form 3949-A (Rev. October 2020), Catalog No. 47872E, OMB 1545-1960 — the PDF the IRS serves on 2026-09-02; the About page adds an online "Form 3949-A Information Referral" tool as a Recent Development
Source checked

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 (Form 14039), tax-preparer misconduct (Forms 14157 and 14157-A), abusive tax schemes (Form 14242), tax-exempt organizations (Form 13909) or a whistleblower award claim (Form 211). The IRS now also offers an online version of the referral, but many people still prefer the PDF because they can draft it carefully and keep a copy. JustFill makes the official PDF fillable in your browser: the AI auto-detects every field and checkbox, you type or dictate your report, and the first clean completed PDF download is included at no charge.

Download the Form 3949-A form PDF — free

The official Form 3949-A (Rev. October 2020) is a free three-page PDF from the IRS at irs.gov/pub/irs-pdf/f3949a.pdf — page 1 is the form, pages 2–3 are the instructions and the definitions of each violation box. It is already a fillable PDF, so there is nothing to buy: fill it in Acrobat Reader, or open the same blank in JustFill to type or dictate every field and checkbox in any browser; the first clean completed PDF download is included at no charge. Print and mail it to the Ogden address on page 1, or use the IRS online referral tool linked from irs.gov/forms-pubs/about-form-3949-a if you would rather not mail anything.

Get the official Form 3949-A PDF from IRS

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, SSN or TIN, date of birth, street address, occupation, email address, marital status and spouse's name of the person you are reporting (items 1a–1k). The form says to leave blank any line you do not know.

Section A2 — Business being reported

Business name, employer identification number (EIN), telephone number, street address, email address and website, if known (items 2a–2i). Complete both item 1 and item 2 when you are reporting a business and its owner.

Section B, line 3 — Alleged violation

Sixteen checkboxes — check all that apply: False Exemption, False Deductions, Multiple Filings, Organized Crime, Unsubstantiated Income, Earned Income Credit, Public/Political Corruption, False/Altered Documents, Unreported Income, Narcotics Income, Kickback, Wagering/Gambling, Failure to Withhold Tax, Failure to File Return, Failure to Pay Tax, and Other (describe in item 5). Page 2 of the form defines each one.

Section B, line 4 — Unreported income and years

Up to six tax years with the dollar amount of unreported income for each, if known, in the form's own format (its example: TY 2010 – $10,000).

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, item 6 — Additional information

Whether books or records are available — do not send them now; the IRS will contact you if they are needed for an investigation — whether you consider the taxpayer dangerous, and the names and addresses of up to two banks or financial institutions they use. Answer only what you can; otherwise leave blank.

Section C, item 7 — Your information (optional)

Your name, telephone number, best time to call and address. The form states this is not required to process your report and that the IRS never shares it with the person or business you are reporting; leave it blank to stay anonymous.

Common mistakes to avoid

  • 1Using Form 3949-A for the wrong complaint. The form's own caution box says not to use it for identity theft (file Form 14039), tax-preparer misconduct (Form 14157, plus 14157-A if the preparer changed or filed your return without permission), abusive tax schemes or promoters (Form 14242), tax-exempt organizations (Form 13909), or an IRS notice that someone claimed your dependent — follow the notice 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.

Form 3949-A example — what a filled-out form looks like

A fictional former employee reports a car-detailing business that paid its staff in cash with no withholding and no W-2s or 1099s. The reporter chooses to stay anonymous, so Section C is left blank.

Section A, item 1 — Individual being reported

Left blank

The report is about the business only; complete both 1 and 2 only when you are reporting a business and its owner.

Section A, item 2a–2b — Business name and EIN

EXAMPLE AUTO DETAILING LLC — EIN unknown, left blank

The form says to leave blank any lines you do not know; a missing EIN does not stop the report.

Section A, items 2c–2i — Contact details

(555) 010-0199 — 300 Sample Road, Reno, NV 89501 — no email or website known

Give the address where the business actually operates so the IRS can identify it.

Section B, item 3 — Alleged violation

Failure to Withhold Tax; Unreported Income

Check every box that applies. The instructions define Failure to Withhold Tax as not withholding Social Security or Medicare taxes from employees, for example treating employees as contractors.

Section B, item 4 — Unreported income and tax years

TY 2025 – $60,000 (estimate)

Use the form's own format (TY year – $ amount) and give your best estimate; leave blank if you have none.

Section B, item 5 — Comments

From 03/2025 to 06/2026 I worked as a detailer at this shop. The owner paid all four workers in cash every Friday, issued no W-2 or 1099 forms, and kept customer cash payments in a separate box that was never rung up. I saw the weekly cash envelopes and the handwritten pay sheet.

Who, what, where, when and how you know — the facts the form asks for. Attach another sheet if you need more room.

Section B, item 6a–6b — Records and safety

6a Books/records available: Yes (not sent) — 6b Dangerous: No

The form says not to send records now; the IRS will contact you if they are needed for an investigation.

Section B, item 6c — Banks used

Example Community Bank, 1 Sample Plaza, Reno, NV 89501

Name and address of any financial institution the taxpayer uses, if known.

Section C, item 7 — Your information

Left blank (anonymous)

The form says this is not required to process the report and is never shared with the person or business reported; give it only if you are willing to be contacted.

These values are made up. They are here to show what belongs on each line, not to be copied — every name, number, and address on your own Form 3949-A has to be your own.

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Frequently asked questions

Yes. Form 3949-A is issued by the IRS and is free to download, complete and submit, online or by mail. JustFill lets you fill it in your browser at no cost, and the first clean completed PDF download is included at no charge.
Download the current blank Form 3949-A (Rev. October 2020) directly from the IRS at irs.gov/pub/irs-pdf/f3949a.pdf, linked from irs.gov/forms-pubs/about-form-3949-a — it is free and already fillable. Then open that PDF in JustFill to complete it online, or skip the PDF entirely and use the online referral tool the IRS links from the same page.
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.
Mail the printed form to Internal Revenue Service, PO Box 3801, Ogden, UT 84409 — the address printed on page 1 and page 3 of the form — or submit it online through the IRS Form 3949-A Information Referral tool linked from irs.gov/forms-pubs/about-form-3949-a. No fax number is published, the IRS does not take referrals by phone, and because of the confidentiality rule in Internal Revenue Code section 6103 you will not receive a status or progress update.
Form 3949-A, Information Referral, is the IRS form for telling the agency that a person or business may be breaking federal tax law — for example hiding income, paying workers in cash without withholding, claiming false deductions or dependents, or not filing returns. It is a tip, not a claim: the IRS decides whether to act, will not tell you what happened, and pays no reward (that is Form 211). The current edition is Rev. October 2020, one page plus two pages of instructions.
Either. The IRS says you can submit Form 3949-A online or by mail: the online route is the Form 3949-A Information Referral tool linked from irs.gov/forms-pubs/about-form-3949-a, and the mail route is the printed form sent to Internal Revenue Service, PO Box 3801, Ogden, UT 84409. There is no fax option and no phone reporting. If you want a copy of exactly what you sent, fill the PDF in JustFill, download it, and mail that.

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

Edition checked: Form 3949-A (Rev. October 2020), Catalog No. 47872E, OMB 1545-1960 — the PDF the IRS serves on 2026-09-02; the About page adds an online "Form 3949-A Information Referral" tool as a Recent Development. Verified against the official source on .

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