DOR Taxation web site


Colorado's fiduciary or estate/trust income tax return starts with the estate's or trust's federal taxable income.  Therefore, the federal deductions and exemptions have already been subtracted.  For this reason, no lines for deductions and exemptions appear on the Colorado form.  Then, on Colorado's 105 form or in any Colorado fiduciary income tax electronic filing option, the state requires certain additions to federal taxable income and offers subtractions from federal taxable income before the estate or trust arrives at its Colorado taxable income.  The Colorado taxable income is then taxed at a flat rate of 4.63 percent. 


A Colorado Account Number is assigned to an estate/trust account when the first tax filing is submitted with a Federal Employer Identification Number (FEIN).  The FEIN is assigned by the Internal Revenue Service (IRS) when the estate or trust is created.  If a Colorado Account Number has been assigned to the estate or trust, it must be entered on the 105 form.


Returns are due the 15th day of the fourth month following the close of the taxable year. An estate or trust is granted an automatic six-month extension of time for filing. If either of these dates fall on a weekend or holiday, the tax should be filed by the next business day. File the return through Revenue Online.


Information regarding the Department of Revenue's transition to a new tax accounting system.