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Income Tax Special Apportionment Rules - Adopted

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On December 13, 2021, the Colorado Department of Revenue, Division of Taxation, adopted three income tax apportionment rules and repealed 21 income tax apportionment rules. The adoption was based on the public rulemaking hearing held on November 3, 2021.

Prior to the public rulemaking hearing, the Department solicited public comment on the rules from August 25, 2021, through September 17, 2021.

Copies of the adopted rules, date of publication in the Colorado Register, and effective dates may be found on the Secretary of State’s website at the links below.


Special Rule 9A. Apportionment of Income for Electricity Producers.


Rule 39-22-303.6–1. Apportionment and Allocation Definitions.

Rule 39-22-303.6–7. Sales Other Than Sales of Tangible Personal Property in Colorado.


Regulation IV. Colorado Multi-state Compact Tax Regulation – Applicability.

Regulation IV.1.(a). Business and Nonbusiness Income Defined.

Regulation IV.1.(b).

Regulation IV.1.(c). Business and Nonbusiness Income: Application of Definitions.

Regulation IV.1.(d). Proration of Deductions.

Regulation IV.2.(a). Definitions.

Regulation IV.2.(b)(1). Application of Article IV: Apportionment.

Regulation IV.2.(b)(2). Application of Article IV: Combined Report.

Regulation IV.2.(b)(3). Application of Article IV: Allocation.

Regulation IV.2.(c). Consistency and Uniformity in Reporting.

Regulation IV.3.(a). Taxable in Another State.

Regulation IV.3.(b). Taxable in Another State: When a Corporation is “Subject to” a Tax under Article IV.3.(1).

Regulation IV.3.(c). Taxable in Another State: When a State Has Jurisdiction to Subject a Taxpayer to a Net Income Tax.

Regulation IV.9. Apportionment Formula.

Regulation IV.15.(a). Sales Factor.

Regulation IV.15.(b). Sales Factor: Denominator.

Regulation IV.15.(c). Sales Factor: Numerator.

Regulation IV.16.(a). Sales Factor: Sales of Tangible Personal Property in this State.

Regulation IV.16.(b). Sales Factor: Sales of Tangible Personal Property to United States Government in this State.

Regulation IV.17. Sales Factor: Sales Other than Sales of Tangible Personal Property in this State.

Regulation IV.18.(c). Special Rules: Sales Factor