Where and how to report tax fraud

You can report suspected tax fraud to the Internal Revenue Service (IRS) using Form 3949-A (Information Referral) or by submitting information online through the IRS website. The IRS Criminal Investigation division handles cases involving deliberate tax evasion, falsified documents, or hidden income. You can also report to your state tax authority — most states have their own fraud hotlines or online reporting systems separate from the federal IRS.

The IRS does not require you to use a specific form. You can write a letter describing what you observed, include supporting documents if you have them, and mail it to the IRS Criminal Investigation office in your region. Online reporting through the IRS website (irs.gov) is faster and does not require you to print or mail anything. State tax agencies typically have their own online portals or phone numbers listed on their department websites.

You do not need to be certain about the fraud to report it. If you have reasonable suspicion — for example, you know someone is running a cash business and reporting no income, or you saw them claim dependents who do not exist — that is enough to file a report. The IRS investigates and determines whether fraud actually occurred.

Key Takeaways

  • Report federal tax fraud to the IRS Criminal Investigation division by mail, phone, or through the IRS website; state tax fraud goes to your state tax authority's fraud hotline or online portal.
  • You do not need proof or certainty — reasonable suspicion of hidden income, false deductions, or fake dependents is enough to report.
  • The IRS keeps your identity confidential if you request it, though some information may become known during investigation or legal proceedings.
  • Reporting does not may provide an investigation or prosecution; the IRS prioritizes cases involving large amounts of money or organized schemes.
  • If you are a whistleblower with direct knowledge of substantial tax fraud, you may be may be able to access for a reward of 15 to 30 percent of taxes recovered above $2 million.

What information to include in your report

Include the person's name, address, and any identifying information you have — Social Security number, business name, or employer identification number if you know it. Describe what you observed or know: dates, amounts, specific transactions, or documents you saw. For example, "I worked at ABC Plumbing from 2022 to 2024 and saw the owner pay workers in cash and not record it on payroll" is more useful than "I think they are cheating on taxes."

Attach copies of any documents you have — pay stubs, invoices, bank statements, business records, or emails — but do not send originals. If you witnessed something directly, describe it clearly: what you saw, when you saw it, and where. If you are reporting based on what someone told you, say that. The IRS will weigh firsthand knowledge more heavily than hearsay, but both can trigger an investigation.

Do not speculate or include accusations you cannot back up. Stick to facts and observations. The IRS has investigators trained to follow leads; your job is to report what you know, not to prove the case.

How to report anonymously

You can report tax fraud without giving your name. When you submit a report to the IRS — whether by mail, phone, or online — you can request that your identity remain confidential. The IRS will not disclose your name to the person being investigated unless you are subpoenaed as a witness in a criminal case, which is rare.

If you report by mail, write "Anonymous" where your name would go. If you report online or by phone, you will be asked whether you want to remain anonymous; select that option. Keep in mind that if the investigation moves to court and you are the only person with knowledge of the fraud, you may be called to testify, which would reveal your identity. This is uncommon but possible in serious cases.

Reporting anonymously does not reduce the weight of your report. The IRS evaluates the information itself, not the source. If you have strong evidence or direct knowledge, anonymous reports are taken seriously.

The IRS whistleblower reward program

If you have direct knowledge of tax fraud and the IRS recovers more than $2 million in taxes, penalties, and interest as a result of your report, you may receive a reward. The reward is 15 to 30 percent of the amount recovered. This program is separate from anonymous reporting — you must identify yourself and provide detailed information to be considered for a reward.

To pursue a whistleblower reward, file Form 211 (Application for Award for Original Information) with the IRS. You will need substantial evidence: documents, transaction records, or testimony showing deliberate tax evasion. The IRS Criminal Investigation division reviews your claim and decides whether to investigate. If they do investigate and recover money, you will be notified of the outcome and the reward amount.

The process typically takes years. The IRS must complete its investigation, any criminal prosecution must conclude, and the government must collect the money before a reward is paid. Whistleblower cases involving large businesses, organized fraud, or hidden offshore accounts are more likely to result in recoveries large enough to trigger a reward.

What happens after you report

The IRS receives thousands of reports each year. Your report goes into a queue for review by Criminal Investigation agents. They assess whether the information suggests fraud and whether the case is worth investigating given their resources. Cases involving large sums of money, organized schemes, or public figures are prioritized. A report about someone underreporting income by a few thousand dollars may not be investigated immediately, if at all.

You will not receive updates on whether an investigation started or what happened. The IRS does not notify reporters of outcomes. If you want to know the status, you can contact the IRS Criminal Investigation office directly, though they may not disclose details about an active investigation.

If the case results in criminal charges, you may learn about it through public court records or news reports. If it results in civil penalties or back taxes owed, that information is typically not public unless the case is high-profile.

Reporting to state tax authorities

Each state has its own tax fraud reporting process. Most states operate a fraud hotline or online reporting portal through their Department of Revenue or Department of Taxation. You can find your state's process by searching "[your state] tax fraud report" or visiting the state tax agency website directly.

State reports are handled separately from federal reports. If you suspect someone is evading both federal and state taxes, you may need to report to both the IRS and your state. State investigators focus on state income tax, sales tax, or business tax fraud. The process and timeline are similar to federal reporting: you provide information, the state reviews it, and you receive no update on the outcome.

Some states offer their own whistleblower reward programs, though they are less common than the federal program. Check your state's tax agency website to see whether a reward program exists.

When you should not report and what to do instead

If you suspect fraud by your employer and you are concerned about retaliation, contact the Occupational Safety and Health Administration (OSHA) whistleblower protection program or an employment attorney before reporting to the IRS. OSHA protects workers who report illegal activity, including tax fraud, from being fired or punished. An attorney can advise you on your rights and the best way to proceed.

If you are unsure whether something is actually fraud — for example, you are not certain whether a deduction is legal or whether income was reported — you can contact the IRS directly to ask. Call the IRS at 1-800-829-1040 and ask to speak with a tax professional. They can explain what is and is not allowed, which may clarify whether you have observed actual fraud.

If you are a former employee with access to company tax records and you are considering reporting, consult an attorney first. Depending on how you obtained the documents and your employment agreement, there may be legal restrictions on what you can disclose.

Frequently Asked Questions

Can I report someone for tax fraud if I only suspect it but have no proof?

Yes. The IRS investigates based on suspicion and reasonable evidence, not proof. If you know someone is running a cash business with no reported income, or you saw them claim dependents they do not support, that is enough to report. The IRS has investigators who will determine whether fraud actually occurred.

Will the person I report find out it was me?

Not unless you are subpoenaed as a witness in a criminal case, which is rare. You can request anonymity when you report, and the IRS will not disclose your name to the person being investigated. If the case goes to trial and you are the only witness, you may be called to testify, which would reveal your identity.

What if I report someone and nothing happens?

The IRS receives thousands of reports and investigates based on priority and available resources. Cases involving small amounts of money or limited evidence may not be investigated. You will not be notified of the outcome. If you have additional evidence later, you can file another report.

Can I get in trouble for reporting false information?

If you knowingly file a false report with the intent to harm someone, you could face legal consequences. However, if you report in good faith based on what you observed or believed to be true, you are protected. Do not speculate or include information you are not confident about.

How long does it take for the IRS to investigate?

There is no set timeline. Some investigations take months; others take years. The IRS does not provide updates to reporters. If the case results in criminal charges or a settlement, you may learn about it through public records, but the IRS will not contact you with a status update.