How to Prepare IRS Form 3949A. If you discover an individual or a business is not submitting a proper tax return for one or more years, you can send that information to the Internal Revenue Service (IRS) on Form 3949A. The submission of such information is voluntary and kept confidential. If you have books and records or other documentation relating to this report, you should retain those records until an investigation is completed.
Download Form 3949A Information Referral from the IRS website. Complete Sections 1 to 3 regarding the individual or business about which you are reporting the tax information.
Check all the items in Section 4 which are violations of income tax law pertaining to the named taxpayer. If your report involves unreported income, complete the information requested in Section 5 as to each specific tax year and the unreported income for that year to the extent known.
Include a brief description of the facts of the tax violation as to who did what and when and how was it done. If you need more space than is provided on the form attach more sheets.
Indicate which banks or other financial institutions, if known, are used by the alleged tax violator, and whether you have pertinent books and records available. Based on your personal knowledge, state if the person should be regarded as dangerous.
Describe how you obtained the information included on this form and include your name, address and telephone number where indicated. Send the completed form to the address shown in the form.