Yes, you can report suspected tax fraud or unreported income to the IRS

The IRS has a formal process for reporting tax violations. You can report someone you believe is not paying taxes they owe, is claiming false deductions, or is underreporting income. The IRS calls this the Whistleblower Program when the report involves substantial tax fraud, and it has a separate channel for general tax violations.

The method you use depends on what you are reporting and whether you have direct knowledge of the violation. Reports can be anonymous, and the IRS will not tell the person being reported who made the report. However, the IRS receives thousands of reports annually and investigates only a fraction of them — usually those involving large amounts of money or organized schemes.

Key Takeaways

  • You can report suspected tax fraud using Form 3949-A (general violations) or Form 211 (the Whistleblower Program for cases involving $2 million or more).
  • Reports can be made online, by mail, or by phone, and you can remain anonymous in all cases.
  • The IRS investigates only a small percentage of reports, prioritizing cases involving large sums or criminal activity.
  • If your report leads to a successful prosecution and recovery of taxes, you may receive a monetary award under the Whistleblower Program, but only if you file Form 211.
  • You do not need to be a tax professional or have formal proof to make a report — suspicion based on direct knowledge is sufficient to file.

Reporting general tax violations using Form 3949-A

For most everyday tax violations — someone working under the table, a business not reporting cash income, inflated deductions — you use Form 3949-A, titled "Information Referral." This is the standard form for reporting suspected tax fraud that does not meet the Whistleblower Program threshold.

You can file Form 3949-A by mail to your regional IRS office or submit it online through the IRS website. The form asks for the person's name, address, and Social Security number or business tax ID if you have it, along with a description of what you believe they are doing wrong. You do not need documentation or proof — a detailed explanation of what you observed is enough to start an investigation.

Mail the form to the IRS Criminal Investigation office in your state, or check the IRS website for the specific address. Processing time varies, but the IRS typically acknowledges receipt within a few weeks. You will not receive updates on whether an investigation was opened or what happened as a result.

Using the Whistleblower Program for larger cases

If you have knowledge of tax fraud involving $2 million or more in unpaid taxes, you can file Form 211 under the IRS Whistleblower Program. This program is designed for people with inside knowledge of substantial tax schemes — employees, accountants, business partners, or others with direct access to financial records.

The key difference between Form 211 and Form 3949-A is that Form 211 can result in a monetary award. If your information leads to a successful prosecution and the IRS recovers taxes, penalties, and interest, you may receive between 15 and 30 percent of the amount recovered, up to a maximum of $10 million. However, you only become may be able to access for an award if you file Form 211; filing Form 3949-A does not may have access to you for payment.

Form 211 requires more detail than Form 3949-A. You will need to describe the violation, explain how you know about it, provide the person's or business's identifying information, and estimate the amount of unpaid taxes involved. You can file by mail or through the IRS Whistleblower office online portal. Processing can take several months, and the IRS will contact you if they decide to investigate.

Reporting online, by phone, or by mail

You have three ways to report: online through the IRS website, by phone, or by mail. The online method is fastest — you can submit Form 3949-A or Form 211 directly through the IRS Whistleblower portal without printing or mailing anything. The portal also allows you to upload supporting documents if you have them.

By phone, you can call the IRS Criminal Investigation tip line at 1-800-366-4484. This line is monitored during business hours, and you can provide information verbally. The agent will take notes and may ask follow-up questions. You do not need to provide your name, though the IRS may ask for contact information if they want to follow up with you later.

By mail, print the form, fill it out completely, and send it to the IRS Criminal Investigation office in your state. Include as much detail as possible about the violation, the person's identifying information, and any documents you can attach (pay stubs, receipts, business records). Mail takes longer — expect two to four weeks for the IRS to receive and log your report.

What happens after you report

After you file a report, the IRS does not automatically investigate. The agency receives over 100,000 reports annually and has limited resources. Reports are screened and prioritized based on the amount of money involved, whether criminal activity is suspected, and whether the IRS already has an open case on the person or business.

If the IRS decides to investigate, they will typically contact the person being reported as part of an audit or criminal investigation. They will not say who reported them — the IRS keeps whistleblower identities confidential. If you filed Form 211 and the case results in a recovery, the IRS will contact you about your award, usually within one to two years of the recovery being finalized.

You will not receive updates on the status of your report unless you filed Form 211 and the case moves forward. The IRS does not confirm whether an investigation was opened, and you will not know the outcome unless the case becomes public (for example, if it results in a criminal prosecution that is reported in the news).

What you need to know about anonymity and retaliation

All reports to the IRS can be made anonymously. You do not have to provide your name, address, or phone number on either Form 3949-A or Form 211. If you do provide contact information, the IRS will keep it separate from the report itself and will not share it with the person being reported.

Federal law protects whistleblowers from retaliation. If you report your employer or someone else and they later fire you, demote you, or take other negative action against you because of the report, you may have grounds for a legal claim. However, proving retaliation can be difficult, and you would need to file a separate complaint with the Department of Labor or pursue a civil lawsuit.

If you are reporting someone you know personally — a family member, friend, or neighbor — consider the relationship consequences before filing. The report is confidential, but investigations can take time, and the person may eventually figure out who reported them based on who knew about the violation.

When the IRS will not investigate your report

The IRS will not investigate reports that are vague, lack identifying information, or involve small amounts of money. If you report someone for claiming a few hundred dollars in false deductions or working a side job without reporting it, the IRS is unlikely to open a case unless they already have the person under investigation for other reasons.

The IRS also does not investigate disputes between individuals over who owes money, disagreements about business arrangements, or personal conflicts. If you are reporting someone out of spite or as part of a personal dispute, the IRS will likely dismiss the report. Reports must be based on a genuine belief that a tax violation has occurred.

If you are unsure whether what you observed constitutes a tax violation, you can call the IRS at 1-800-829-1040 and ask a general question about tax law. You do not need to name the person or provide details — you can ask hypothetically. This helps you determine whether filing a report makes sense.

Frequently Asked Questions

Can I report someone anonymously?

Yes. You do not have to provide your name, address, or phone number on Form 3949-A or Form 211. If you do provide contact information, the IRS keeps it separate from the report and does not share it with the person being reported.

What if I don't have the person's Social Security number or tax ID?

Provide whatever identifying information you have — their full name, address, business name, and phone number. The IRS can often locate someone with just a name and address. The more detail you provide, the easier it is for the IRS to find the right person and investigate.

Can I get paid for reporting someone?

Only if you file Form 211 and the case involves $2 million or more in unpaid taxes. If the IRS recovers money as a result of your report, you may receive 15 to 30 percent of the recovery. Filing Form 3949-A does not make you may be able to access for an award.

How long does it take for the IRS to investigate?

There is no set timeline. The IRS may begin investigating within weeks or may take months to prioritize your report. Some reports are never investigated due to limited resources. If you filed Form 211, the IRS will contact you if they decide to move forward.

Will the person know I reported them?

Not from the IRS. The agency keeps whistleblower identities confidential. However, if the investigation becomes public or results in a prosecution, the person may figure out who reported them based on who had access to the information.