To report someone to the IRS for suspected tax fraud, submit Form 3949-A, the agency’s information referral form, either online or by mail to the IRS in Ogden, Utah. If your complaint is about a paid tax return preparer, use Form 14157 instead. And if you have detailed inside information about a large violation and want to be paid for it, file Form 211 with the IRS Whistleblower Office.
Which Form to Use
The right form depends on who you’re reporting and whether you want a financial reward.
Form 3949-A for General Tax Fraud
Form 3949-A is the standard referral for reporting an individual or business you believe is cheating on taxes. It covers unreported income, false deductions, altered documents, employment tax violations, failure to file, and similar misconduct.1Internal Revenue Service. About Form 3949-A, Information Referral The form asks for details about the taxpayer, a description of what they did, and optionally your own contact information. File it online through the IRS website or mail it to:
Internal Revenue Service
PO Box 3801
Ogden, UT 84409
Form 14157 for Tax Preparer Misconduct
If the problem is a paid preparer who filed a return without your permission, inflated deductions without telling you, or redirected your refund, use Form 14157.2Taxpayer Advocate Service. Tax Return Preparer Fraud Victims of preparer fraud (as opposed to third-party witnesses) also complete Form 14157-A, the preparer fraud affidavit. You can submit online, by fax, or by mail to:
Internal Revenue Service
Attn: Return Preparer Office
401 W. Peachtree Street NW
Mail Stop 421-D
Atlanta, GA 303083Internal Revenue Service. Make a Complaint About a Tax Return Preparer
Form 211 for Whistleblower Awards
Form 211 is the form to use when you have specific, credible information about a significant tax violation and want to be considered for a monetary award.4Internal Revenue Service. Submit a Whistleblower Claim for Award It requires a description of the violation, the tax years involved, and your estimate of how much revenue the government is losing. You sign it under penalty of perjury. File electronically through the IRS website or mail it to:5Internal Revenue Service. Whistleblower Office Announces New Digital Form 211
Internal Revenue Service
Whistleblower Office – ICE
1973 N. Rulon White Blvd.
M/S 4110
Ogden, UT 84404
What to Include in Your Report
The IRS is more likely to act on a tip that identifies the taxpayer clearly and explains what happened in concrete terms. Try to gather:
- The person’s or business’s full legal name and current address, plus a Social Security Number or Employer Identification Number if you have it.
- A written description of what the person did, how you found out, and the approximate dollar amounts.
- The tax years you believe the fraud covers.
- Any supporting documents you can attach, such as bank statements, ledger entries, canceled checks, contracts, emails, or text messages.
You don’t need all of this to file. The IRS accepts reports even without an SSN or paperwork. But the more specific and verifiable your information, the better the odds the agency will follow up.
Can You Report Anonymously
Yes. Form 3949-A can be filed without your name or contact information; the form itself states that personal information is not required to process the report.6IRS.gov. Form 3949-A, Information Referral The tradeoff is that the IRS cannot come back to you for clarification, which can weaken an otherwise useful tip.
If you do give your name, federal law protects it. Under 26 U.S.C. § 6103, the IRS is generally barred from disclosing return information in a way that would identify a confidential informant, and that restriction reaches even sharing with state tax officials, the Department of Justice, and courts.7Office of the Law Revision Counsel. 26 U.S. Code 6103 – Confidentiality and Disclosure of Returns and Return Information The protection is not absolute. If your report leads to a criminal prosecution and prosecutors need your testimony, a court can require disclosure, and the IRS may share information with the Department of Justice to enforce tax laws.
If You’re Reporting Your Employer
Employees who report suspected tax violations have specific anti-retaliation protection. Under 26 U.S.C. § 7623(d), added by the Taxpayer First Act of 2019, an employer cannot fire, demote, suspend, threaten, harass, or otherwise punish an employee for reporting suspected tax violations to the IRS, the Department of Justice, Congress, or even a supervisor.8Office of the Law Revision Counsel. 26 USC 7623 – Expenses of Detection of Underpayments and Fraud, Etc.
If your employer retaliates, you file a complaint with the Secretary of Labor. If the Department of Labor hasn’t issued a final decision within 180 days, you can take the case to federal court yourself. A winning employee is entitled to reinstatement, double back pay with interest, full lost benefits, and reimbursement of attorney fees, expert witness costs, and other litigation expenses.9Whistleblower Protection Program. Taxpayer First Act (TFA) Pre-employment waivers and mandatory arbitration clauses cannot override these rights.
Whistleblower Awards
The IRS pays awards to people whose information leads to actual collection of unpaid taxes, penalties, and interest. There are two tracks, and the one you fall into depends on the size of the case.
The mandatory award program applies when the total amount in dispute (tax, penalties, and interest combined) exceeds $2 million. For cases against individuals, the taxpayer must also have had gross income above $200,000 in at least one of the years at issue. Cases against businesses or other entities need only clear the $2 million threshold. A successful mandatory claim pays between 15 and 30 percent of what the IRS collects, with the percentage set by how much the whistleblower’s information contributed.8Office of the Law Revision Counsel. 26 USC 7623 – Expenses of Detection of Underpayments and Fraud, Etc.
Even inside that range, the award can be cut. If the case rested mainly on information already available through government reports, court filings, or news coverage, the ceiling drops to 10 percent. If the whistleblower planned or started the conduct, the IRS can reduce the award further, and a criminal conviction for that role wipes it out entirely.10Office of the Law Revision Counsel. 26 U.S. Code 7623 – Expenses of Detection of Underpayments and Fraud, Etc.
Claims that don’t meet the $2 million and income thresholds fall under the IRS’s discretionary award authority. The agency decides case by case whether to pay anything, and the statute does not set a percentage cap. Under either track, nothing is paid until the IRS has actually collected from the taxpayer.
What Happens After You Submit
The IRS does not investigate every tip. It weighs each report against the specificity and credibility of the information and the potential revenue at stake. If the agency does pursue the matter, it does so internally, and you will not be involved in or updated on the investigation. Federal law restricts the IRS from sharing information about another taxpayer’s case, so in most instances you will never learn whether your report led to enforcement.
Whistleblower claims filed on Form 211 go through an initial review by the Whistleblower Office and, if they have merit, are referred to the appropriate IRS division. These cases often take several years because the IRS has to complete its examination, collect the taxes, and let the taxpayer’s appeal rights run out before an award can be calculated. You may receive periodic status updates, but details about the underlying case will be limited.
The Risk of Making a False Report
Deliberately filing a false tax fraud report is itself a federal crime. Under 18 U.S.C. § 1001, knowingly making a false or fraudulent statement to a federal agency is punishable by a fine, up to five years in prison, or both, whether you filed on paper or online.11Office of the Law Revision Counsel. 18 U.S. Code 1001 – Statements or Entries Generally Form 211 adds a signature under penalty of perjury, which carries its own exposure. If you’re honestly uncertain whether what you saw is illegal, that uncertainty is not a crime; the statute targets deliberate fabrication, not good-faith mistakes.