Last reviewed: June 1, 2026 · Written by James Carter, Consumer Rights Researcher · Independent resource — not a government site
Report tax fraud to the IRS at irs.gov/individuals/how-do-you-report-suspected-tax-fraud-activity or call 1-800-829-0433. Whistleblowers may earn 15-30% of amounts collected through the IRS Whistleblower Office.
Quick answer: Report tax fraud to the IRS at irs.gov/individuals/how-do-you-report-suspected-tax-fraud-activity or call 1-800-829-0433. For significant fraud ($2M+ individual / $200K+ business), file Form 211 with the IRS Whistleblower Office — awards range from 15-30% of collected proceeds.
Tax fraud costs the U.S. government over $441 billion per year. Whether you’ve discovered an employer under-reporting income, a tax preparer filing fraudulent returns, or a large-scale tax evasion scheme, reporting it protects the tax system and may qualify you for substantial financial rewards.
Types of Tax Fraud You Can Report
The IRS investigates all types of tax fraud including: businesses paying employees under the table to avoid payroll taxes, individuals failing to report cash income, tax preparers inflating deductions or falsifying returns, identity theft and fraudulent refund claims, failing to file returns while earning taxable income, and corporations hiding income offshore or through shell companies.
Where to Report Tax Fraud
| Type of Tax Fraud | Agency | Contact |
|---|---|---|
| General tax fraud / evasion | IRS Criminal Investigation | irs.gov | 1-800-829-0433 |
| Large-scale fraud ($2M+ individual) | IRS Whistleblower Office | irs.gov/whistleblower (Form 211) |
| Under-the-table employment | IRS + Department of Labor | Form 3949-A |
| Tax preparer fraud | IRS Return Preparer Office | irs.gov |
| Tax identity theft | IRS Identity Protection | irs.gov | 1-800-908-4490 |
How to Report Tax Fraud Step by Step
- Determine which form to file. For amounts under $2M, use Form 3949-A (Information Referral). For large fraud ($2M+ individual / $200K+ business), use Form 211 (Whistleblower Claim) which qualifies for rewards.
- Gather all supporting documentation. Collect tax returns, W-2s, 1099s, bank statements, invoices, emails, contracts, and any other evidence that proves fraud occurred. The IRS prioritizes cases with strong documentation.
- Complete Form 3949-A or Form 211. Include the taxpayer’s name, address, SSN or EIN if known, the type of violation, the years involved, and a detailed description of the fraud. Be as specific as possible.
- Submit your report to the IRS. Mail Form 3949-A to: IRS Fresno, CA 93888. For Form 211 (whistleblower claims), mail to: IRS Whistleblower Office, 1111 Constitution Avenue NW, Washington, DC 20224. You can also fax to 877-477-9135.
- Decide whether to report anonymously. Form 3949-A can be filed anonymously, but Form 211 (whistleblower) cannot — you must provide your contact info to claim a reward. Anonymous tips are investigated but you won’t receive updates.
- Report to your state tax agency if applicable. Many states have their own tax fraud hotlines and whistleblower programs. Search “[your state] tax fraud reporting” to find your state’s program.
- Consult a whistleblower attorney if filing Form 211. For large fraud cases, an attorney experienced in IRS whistleblower claims can maximize your award and protect your rights. Most work on contingency.
- Protect yourself from retaliation. IRS whistleblower protections prohibit retaliation by employers. If you experience retaliation, file a complaint with the IRS Whistleblower Office and OSHA within 30 days.
IRS Whistleblower Rewards
Under the IRS Whistleblower Program, you can receive 15-30% of the proceeds collected if the case involves at least $2 million (individual) or $200,000 (business). Awards are paid after the IRS collects the taxes, penalties, and interest — which can take 3-7 years. The largest IRS whistleblower award to date was $104 million paid in 2012.
Frequently Asked Questions
For related guides see: How to Report Someone to the IRS, How to Report Under the Table Wages, and our Fraud & Scams Reporting Hub.