When you (the taxpayer) do not file tax returns within a certain time period, the Internal Revenue Service (IRS) files it for you. This is called a Substitute for Return (SFR). When the IRS files an SFR for you it is their best guess. When this happens, the amount of the tax liability is greatly exaggerated due to the fact that the IRS will file for you at the highest rate and you will not get all deductibles that you may qualify for. Most of the time, simply filing your tax returns greatly reduces your proposed tax liability. More than likely, you will have a lot of penalties and interest, and once the returns have been filed, if you have reasonable cause, you can request a penalty abatement to eliminate some of the penalties and interest that you (the taxpayer) may have accrued over the years.