Where and how to report suspected tax fraud

The IRS has a dedicated channel for reporting suspected tax fraud: the Form 13909, also called the Fraud Referral Form. You file it with the IRS Criminal Investigation division, which is separate from the regular tax examination process. You can submit the form by mail, fax, or through the IRS website's online whistleblower portal.

The fastest route is usually the online portal at www.irs.gov/fraud, where you can upload documents and describe what you observed. If you mail or fax the form, send it to the IRS Criminal Investigation office in your region — the IRS website lists regional addresses. Faxing typically reaches the office faster than mail.

You do not need to be a tax professional or have complete proof to file. The IRS accepts reports from anyone who suspects fraud, whether you are a business owner, employee, customer, or someone who simply noticed something wrong on a tax return you saw. The form asks for specific details about what happened, who was involved, and when, but you can describe what you know even if you do not have every document.

Key Takeaways

  • File Form 13909 with IRS Criminal Investigation through the online portal at www.irs.gov/fraud, by mail, or by fax to report suspected tax fraud.
  • You can report fraud even if you do not have complete documentation — describe what you observed and let the IRS investigate.
  • The IRS keeps your identity confidential if you request it, though the agency may need to contact you for clarification.
  • If you are a whistleblower with inside knowledge of substantial fraud, you may be may have access to to a reward under the IRS Whistleblower Program, but only if specific conditions are met.
  • Criminal Investigation typically handles cases involving intentional evasion, false documents, or organized schemes — not simple mistakes or aggressive tax positions.

What counts as tax fraud versus a mistake

Tax fraud requires intent — the person knowingly filed a false return or hid income on purpose. If someone made an honest error, forgot to report income, or misunderstood a rule, that is not fraud, even if the IRS later assesses penalties. Criminal Investigation focuses on deliberate deception: claiming fake deductions, hiding cash income, inflating business expenses, creating false documents, or using someone else's identity or Social Security number.

Aggressive tax positions — claiming deductions the IRS might disallow or interpreting a rule in your favor — are not fraud either. The line is intent. If a business owner genuinely believed a deduction was legal but the IRS disagrees, that is a tax dispute. If the owner invented receipts or hid the expense entirely, that is fraud.

The IRS Examination division handles most tax disputes and errors. Criminal Investigation steps in when the evidence suggests someone acted knowingly and deliberately. If you are unsure whether something is fraud or a mistake, describe what you observed in your report and let the IRS determine whether to investigate.

What information to include in your report

Form 13909 asks for the name and address of the person or business you are reporting, their Social Security number or Employer Identification Number if you have it, and the tax years involved. Describe what happened: Did they claim deductions they did not have? Did they hide income? Did they file returns for people who did not exist? Include dates, amounts, and any documents you have seen — receipts, emails, bank statements, or the actual tax return if you have access to it.

Explain how you know about the fraud. Are you a current or former employee? A customer? Someone who saw a return? The IRS uses this context to assess how reliable your information is. If you have documents, upload them with your online report or attach them to a mailed form. If you do not have documents, write down what you remember: specific conversations, dates when you saw something suspicious, or patterns you noticed over time.

You do not need to solve the case. You are providing leads. The IRS Criminal Investigation division has subpoena power, forensic accountants, and access to bank records — tools you do not have. Your job is to report what you observed clearly enough that an investigator can decide whether to open a case.

Confidentiality and whistleblower protections

You can request that the IRS keep your identity confidential when you file Form 13909. Check the box on the form, and the IRS will not disclose your name to the person or business you reported. However, confidentiality has limits: if the case goes to trial, you may be required to testify, which would reveal your identity. The IRS also may need to contact you during the investigation to clarify details, which means they will know who you are even if the subject of the investigation does not.

Federal law protects whistleblowers from retaliation. If you report fraud and your employer or someone else punishes you for it — firing you, cutting your pay, or harassing you — that retaliation is illegal. If retaliation happens, you can file a complaint with the Occupational Safety and Health Administration (OSHA) or consult an employment attorney. Keep records of any adverse action taken against you after you report.

The IRS Whistleblower Program and potential rewards

If you have inside knowledge of substantial tax fraud — meaning the unpaid taxes, penalties, and interest total more than $2 million — you may be may have access to to a monetary reward under the IRS Whistleblower Program. The reward is a percentage of the money the IRS collects as a result of your information, typically between 15 and 30 percent.

To pursue a whistleblower claim, file Form 211 (Application for Award for Original Information) instead of or in addition to Form 13909. Form 211 is more formal and triggers a specific process: the IRS examines your claim, investigates the fraud, and if they collect money, calculates your reward. This process takes years, not months. You should consult a tax attorney or whistleblower attorney before filing Form 211, because the rules are complex and your claim must meet specific requirements.

The $2 million threshold is firm — smaller cases do not may have access to for rewards. Also, you cannot have obtained your information through your job as a government employee or tax professional bound by confidentiality rules. If you are a CPA or attorney, you have ethical obligations that may prevent you from reporting certain client information, even if fraud occurred. An attorney can advise you on what you can and cannot disclose.

What happens after you report

After you file Form 13909, the IRS Criminal Investigation division reviews your report. They do not send you a confirmation or update you on progress. If they decide to investigate, they will open a case file, but you will not hear about it unless you filed a whistleblower claim under Form 211, in which case you may receive periodic updates.

Criminal Investigation prioritizes cases based on the amount of money involved, the sophistication of the scheme, and the likelihood of prosecution. A report about a small business owner hiding cash income may take years to investigate or may not be pursued at all if resources are limited. A report about organized fraud affecting many people or a large amount of money moves up the queue.

You should not expect the IRS to tell you the outcome. Criminal investigations are confidential. If the case results in prosecution, you may learn about it through public court records or news reports, but the IRS will not contact you to say whether they acted on your report.

Reporting fraud you witnessed at work

If you discovered fraud while employed by the company or business involved, you have several options. You can report internally to management, compliance, or an ethics hotline if your employer has one. You can also report to the IRS directly using Form 13909. These are not mutually exclusive — you can do both.

If you report internally and face retaliation, document it carefully: dates, what was said, who witnessed it, and any written communications. Retaliation for reporting fraud is illegal under federal whistleblower laws. If you then report to the IRS or OSHA, include the retaliation in your complaint.

If you are concerned about retaliation before you report, consult an employment attorney first. They can advise you on your specific situation and help you understand your protections. Some attorneys work on contingency for whistleblower cases, meaning you do not pay unless you recover money.

Frequently Asked Questions

Can I report tax fraud anonymously?

You can request confidentiality on Form 13909, which keeps your name from the person you reported. However, the IRS will know who you are, and if the case goes to court, you may be required to testify and reveal your identity. True anonymity — where no one knows who you are — is not possible when reporting to a government agency.

What if I am not sure whether something is fraud or just a mistake?

Report it anyway. Describe what you observed and let the IRS determine whether it meets the threshold for fraud. If it turns out to be an honest error, no harm is done. If it is fraud, your report helps the IRS catch it. The form does not require you to prove fraud — only to report what you saw.

How long does the IRS take to investigate a fraud report?

There is no set timeline. Criminal Investigation prioritizes cases based on the amount of money and complexity. Small cases may take years or may not be pursued. Large or organized fraud schemes may move faster. You will not receive updates unless you filed a whistleblower claim under Form 211.

Can I get in trouble for reporting fraud if I was involved in it?

Reporting fraud does not automatically protect you from prosecution if you participated in it. However, cooperating with the IRS and providing detailed information can influence how prosecutors and judges view your role. Consult a criminal tax attorney before reporting if you were involved, because they can advise you on your exposure and help you negotiate with authorities.

What if the person I am reporting is a family member?

You can report family members to the IRS. There is no family exemption from tax law. If you are concerned about the relationship impact, you can request confidentiality on the form. The IRS will not tell them who reported them, though they may figure it out during an investigation.