What Is IRS Form 3949-A? Reporting Tax Fraud and Filing Steps

IRS Form 3949-A is the Information Referral, the form used to report suspected tax law violations by an individual, a business, or both.¹ Anyone can file it, and you can do so anonymously. It covers a wide range of misconduct, from unreported income and false deductions to organized crime and never filing a return. One thing it does not do: get you paid. If you want a financial award for what you know, a separate form handles that, and it’s covered further down.

What You Can Report on Form 3949-A

The form fits most of the everyday tax cheating the IRS sees. You can report someone who fails to report income, claims deductions or exemptions they aren’t entitled to, uses false or altered documents, or simply never files.¹ Employers who don’t withhold income, Social Security, or Medicare taxes from wages are common subjects, as are cash-heavy businesses that skim receipts and employers paying workers off the books.

It also reaches more serious conduct: organized crime, illegal kickbacks, income from illegal drug sales or gambling operations, Earned Income Credit fraud, and public or political corruption.²

When a Different Form Is the Right One

Not every tax complaint belongs on 3949-A. Sending your information through the wrong channel can delay or derail it.

If someone used your Social Security number to file a fraudulent return, or you received IRS notices about income you never earned, file Form 14039, Identity Theft Affidavit. That form protects you as a victim. Form 3949-A is for reporting someone else’s violations.³
If you suspect a charity or other tax-exempt organization is misusing funds, running a for-profit operation, engaging in political campaign activity, or failing to file required returns, use Form 13909 instead. It goes to the Tax Exempt and Government Entities Division in Dallas.⁴
If a tax preparer or promoter is pushing fraudulent refund schemes, false credits, or suspicious entity structures, use Form 14242. It targets the people designing and selling the scheme, not just the taxpayer benefiting from it.⁵

What Information to Have Ready

Detail is what makes a referral usable. Start with the subject’s full legal name and current street address. If you have a Social Security number or Employer Identification Number, include it. Those identifiers let the IRS match your referral to actual tax records immediately.⁶

The form asks for the estimated dollar amount of unreported income or underpaid tax and the specific tax years involved. Exact figures aren’t required. A reasonable estimate is fine. Vague claims with no numbers and no time frame give investigators little to work with.

You also need to describe the facts: who is doing what, where, when, and how you know. If you have supporting documents like bank statements, contracts, or payment records, attach copies. Don’t send originals. The IRS will contact you if it needs them later.⁶

Your own contact information is optional. Providing it lets investigators follow up if they need clarification, but leaving it off doesn’t stop the referral from being processed. The IRS states it will never share your identity with the person or business you report.⁶

How to Submit the Form

The IRS accepts Form 3949-A through an online submission experience on IRS.gov, so you no longer have to print and mail a paper copy.¹ The online version walks through the same fields as the paper form.

If you’d rather mail it, download the PDF from IRS.gov and send the completed form to:

Internal Revenue Service
PO Box 3801
Ogden, UT 84409⁶

Keep copies of everything you submit.

What Happens After You File

IRS staff screen the referral to decide whether it warrants an audit, examination, or criminal investigation. You almost certainly won’t hear back. Under 26 U.S.C. § 6103, tax return information is confidential, which means the IRS generally cannot tell you whether it opened a case, assessed additional taxes, or did nothing at all.⁷

There’s one exception. If you also file a whistleblower claim on Form 211 and the IRS proceeds with an action based on your information, the law requires the IRS to notify you within 60 days after the case is referred for audit and again within 60 days after the taxpayer makes a payment.⁷ Without a Form 211 on file, your involvement typically ends when you hit submit.

Processing times vary. A simple case of unreported income can move quickly. A scheme involving multiple entities, offshore accounts, or years of fraudulent returns takes far longer. The IRS will contact you only if it needs additional documentation or testimony.

If You Want a Reward, File Form 211 Too

Form 3949-A by itself entitles you to nothing. If you want a financial award for information that leads to the IRS collecting additional taxes, file Form 211, Application for Award for Original Information, with the IRS Whistleblower Office.⁸ This is the step most reporters skip, and it’s the difference between doing the government a favor and being paid for it.

When the taxes, penalties, and interest in dispute exceed $2 million, and, for an individual taxpayer, that person’s gross income exceeds $200,000 in at least one of the relevant years, the award is mandatory. The Whistleblower Office must pay between 15% and 30% of what it collects because of your information.⁹ The percentage depends on how substantially your information contributed. If the IRS was already pursuing the taxpayer from other sources and your tip played a smaller role, the cap drops to 10%.

Claims below the $2 million threshold are evaluated for a discretionary award under a separate provision of the same statute. The IRS has more flexibility there and isn’t bound by the 15–30% range.⁸ Those awards tend to be smaller.

If you planned or initiated the fraud you’re reporting, the Whistleblower Office can reduce your award. If you’re convicted of criminal conduct related to the scheme, the award is denied entirely.⁹

Protection From Employer Retaliation

If the violations you report involve your employer, federal law prohibits retaliation. Under 26 U.S.C. § 7623(d), your employer cannot fire, demote, suspend, threaten, harass, or otherwise punish you for providing information to the IRS, cooperating with an investigation, or testifying in a related proceeding.⁹

If your employer retaliates anyway, you can file a complaint with the Secretary of Labor within 180 days. If the Department of Labor doesn’t issue a final decision within 180 days, you can bring a lawsuit in federal district court. Remedies for employees who prevail include reinstatement, double back pay, full lost benefits with interest, litigation costs, and attorney fees.¹⁰ These protections cannot be waived through employment agreements or forced-arbitration clauses.

1
Internal Revenue Service. About Form 3949-A, Information Referral
2
Internal Revenue Service. Report Tax Fraud, a Scam or Law Violation
3
Internal Revenue Service. When to File an Identity Theft Affidavit
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Internal Revenue Service. IRS Complaint Process – Tax-Exempt Organizations
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Internal Revenue Service. Form 14242 Report Suspected Abusive Tax Promotions or Preparers
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Internal Revenue Service. Form 3949-A (Rev. 10-2020) Information Referral
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Office of the Law Revision Counsel. 26 USC 6103 – Confidentiality and Disclosure of Returns and Return Information
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Internal Revenue Service. Submit a Whistleblower Claim for Award
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Office of the Law Revision Counsel. 26 USC 7623 – Expenses of Detection of Underpayments and Fraud, Etc.
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Office of the Law Revision Counsel. 26 U.S. Code 7623 – Expenses of Detection of Underpayments and Fraud, Etc.