Corporate Income Tax Guide

Colorado imposes a tax on the income of any C corporation that is doing business in Colorado. The tax applies generally to every C corporation that is organized or commercially domiciled in Colorado and to every C corporation that has property, payroll, or sales in Colorado in excess of certain thresholds.

Any C corporation that is subject to Colorado income tax is required to file an annual Colorado income tax return. If certain criteria are met, affiliated C corporations may be required to file a combined return, may elect to file a consolidated return, or may file a combined/consolidated return.

Colorado income tax is based generally on federal taxable income, although various modifications and adjustments are made in the calculation of Colorado income tax. Colorado law requires certain additions, and permits certain subtractions, from federal taxable income.

C corporations that have income from business activity outside of Colorado must apportion and allocate their income to determine the share of their income attributable to Colorado. Apportionment is based generally on the location of the market for the C corporation’s sales. Additionally, a C corporation that has foreign source income will exclude a portion of such income from the calculation of the apportioned Colorado income.

C corporations are generally required to make quarterly estimated payments. A C corporation that fails to make required quarterly estimated payments is subject to a penalty for such failure. However, the penalty generally will not apply if the C corporation’s net tax liability for the tax year is less than $5,000.

This publication is designed to provide taxpayers with general guidance regarding the imposition of Colorado income tax on C corporations, the calculation of the tax, filing of returns, and other related requirements. Nothing in this publication modifies or is intended to modify the requirements of Colorado’s statutes and regulations. Taxpayers are encouraged to consult their tax advisors for guidance regarding specific situations.