You can report someone for not filing taxes to the IRS by submitting Form 3949-A, the agency’s “Information Referral.” You can fill it out online, or print the PDF and mail it to Internal Revenue Service, PO Box 3801, Ogden, UT 84409.1Internal Revenue Service. About Form 3949-A, Information Referral Reports can be anonymous. If you want a financial award instead, that requires a different form and giving up your anonymity.
What Goes on Form 3949-A
The form asks for whatever you know about the person or business, including:
- Full name, address, Social Security or taxpayer ID number, date of birth, and occupation.
- The tax years you believe they failed to file or underreported.
- A description of the violation and how you learned about it.
- Any supporting documents or records that back up your claim.
You don’t need every field filled in. The IRS instructs you to leave blank anything you can’t answer.2IRS. Form 3949-A (Rev. 10-2020) Information Referral But a vague tip with no identifying details is unlikely to go anywhere. A name, an approximate income range, and a clear description of the violation give the agency something to work with.
Form 3949-A covers more than just unfiled returns. The IRS uses it for unreported income, false deductions, failure to withhold taxes, and organized crime, among other categories.3Internal Revenue Service. Report Tax Fraud, a Scam or Law Violation Identity theft and tax preparer misconduct use different reporting channels.
Anonymous Report or Whistleblower Claim
The choice between these two paths shapes almost everything that follows.
An anonymous report on Form 3949-A is simple. You don’t have to identify yourself, and the IRS accepts the tip either way.3Internal Revenue Service. Report Tax Fraud, a Scam or Law Violation You get no updates, no follow-up, and no possibility of an award. If your goal is just to put the information in the IRS’s hands, this is the route.
A formal whistleblower claim uses a separate form, Form 211, “Application for Award for Original Information,” submitted to the IRS Whistleblower Office.4Internal Revenue Service. Form 211 – Whistleblower Office You must identify yourself, provide contact information, and sign under penalty of perjury.5Internal Revenue Service. Submit a Whistleblower Claim for Award Anonymous tips don’t qualify for awards. You trade anonymity for a chance at a payout if the IRS collects.
How Whistleblower Awards Work
The program has two tiers.
For large cases, awards are mandatory. If the taxes, penalties, and interest in dispute exceed $2 million, or the person’s gross income tops $200,000 in any year at issue, you receive 15% to 30% of what the IRS collects. The exact percentage depends on how much your information contributed.6Office of the Law Revision Counsel. 26 USC 7623 – Expenses of Detection of Underpayments and Fraud, Etc. On a $3 million collection, that’s $450,000 to $900,000.
Smaller cases fall under discretionary awards. The IRS still has authority to pay, but the statute leaves the amount to the agency’s judgment.6Office of the Law Revision Counsel. 26 USC 7623 – Expenses of Detection of Underpayments and Fraud, Etc. These awards tend to be smaller and harder to predict.
Two eligibility points catch people out. Your information must be submitted under penalty of perjury, or no award can be paid. And Department of Treasury employees are ineligible.6Office of the Law Revision Counsel. 26 USC 7623 – Expenses of Detection of Underpayments and Fraud, Etc.
What You’ll Hear Back
The IRS screens each referral to decide whether to investigate. Not every tip triggers action; the agency weighs credibility and how much revenue is potentially at stake.
If you sent in a Form 3949-A, you will hear nothing. Federal law prohibits the IRS from disclosing taxpayer return information, so the agency cannot tell you whether it investigated, what it found, or what happened.7Office of the Law Revision Counsel. 26 USC 6103 – Confidentiality and Disclosure of Returns and Return Information Your tip goes into a black box.
Form 211 whistleblowers get much more. The same confidentiality statute carves out specific rights for them: the IRS must notify you within 60 days after your case is referred for audit, and again within 60 days after the taxpayer pays anything related to your information. You can also make written requests for status updates and, if an award is determined, the reasoning behind it.7Office of the Law Revision Counsel. 26 USC 6103 – Confidentiality and Disclosure of Returns and Return Information That visibility is one of the practical reasons people choose the whistleblower route.
If You’re Reporting Your Employer
Federal law protects employees from retaliation for reporting tax violations. An employer cannot fire, demote, suspend, threaten, harass, or otherwise punish you for reporting to the IRS, the Department of Justice, Congress, or an internal supervisor with authority to investigate misconduct. The protection also covers testifying or participating in an IRS enforcement action.6Office of the Law Revision Counsel. 26 USC 7623 – Expenses of Detection of Underpayments and Fraud, Etc.
If retaliation happens anyway, you can file a complaint with OSHA, which investigates whistleblower retaliation claims and can order reinstatement, back pay, and restoration of benefits. The IRS also protects whistleblower identities to the fullest extent the law allows; disclosure to the reported taxpayer is uncommon and usually only occurs if you become an essential witness in court.5Internal Revenue Service. Submit a Whistleblower Claim for Award
What the Person You Report Could Face
Understanding the consequences helps frame what a report actually sets in motion.
On the civil side, failure to file carries penalties of 5% of the unpaid tax per month, capped at 25%, plus interest running from the original due date.8Internal Revenue Service. Topic No. 653, IRS Notices and Bills, Penalties and Interest
On the criminal side, willful failure to file is a federal misdemeanor punishable by up to one year in prison, a fine of up to $25,000 ($100,000 for corporations), or both.9Office of the Law Revision Counsel. 26 U.S. Code 7203 – Willful Failure to File Return, Supply Information, or Pay Tax The government has to prove willfulness, meaning a deliberate choice not to file. Criminal prosecutions for non-filing are uncommon but do happen in serious cases.
One detail makes unfiled returns particularly exposed: when a required return is never filed, no statute of limitations runs. The normal three-year assessment window starts only when a valid return is filed.10Office of the Law Revision Counsel. 26 U.S. Code 6501 – Limitations on Assessment and Collection Someone who skipped filing a decade ago is still fully open to IRS enforcement today.
The Risk if You Make It Up
Reports filed out of spite, in the middle of a divorce, or as a business tactic carry real legal exposure. Knowingly making a false statement to a federal agency is a crime punishable by up to five years in prison and a fine.11Office of the Law Revision Counsel. 18 U.S. Code 1001 – Statements or Entries Generally That applies to materially false statements on Form 3949-A or Form 211.
You can also be sued. Someone who willfully files a fraudulent information return about another person can be held civilly liable. The target can recover the greater of $5,000 or actual damages, plus court costs and potentially attorney fees.12Office of the Law Revision Counsel. 26 U.S. Code 7434 – Civil Damages for Fraudulent Filing of Information Returns File a report only if you have a genuine, good-faith basis for it.
State Taxes Are Separate
Form 3949-A only covers federal taxes. If the person isn’t filing state returns, contact the relevant state department of revenue or taxation directly. Most states run their own fraud reporting systems, and some accept anonymous tips. Forms and procedures vary by state, so check your state revenue department’s website. State penalties are assessed independently of any federal consequences.