Filing Combined Reporting Returns

Combined reporting contrasted with consolidated returns

For federal purposes, a unitary group may be filing a federal consolidated return. Idaho law doesn’t provide for the filing of a consolidated return. Instead, a unitary group must use the combined reporting method. The combined report is often confused with a consolidated return, but they aren’t the same.

The combined reporting method doesn’t refer to whether the unitary group files one or more returns. If you file a single return for the group, this is called a group return, and discussed in the next section.

Some differences between a combined report and a federal consolidated return include the following:

Idaho Combined ReportFederal Consolidated Return
Computation of tax liabilityEach corporation required to file in Idaho computes its own Idaho tax liability, net operating loss, and creditsThe affiliated group computes a single income tax liability for the group
Who can be includedUnitary group – Parent-subsidiary and brother-sister corporation groupsAffiliated group – Only parent-subsidiary groups
Common ownership requirementMore than 50%80% or more

Group return

For convenience, Idaho allows a unitary group to file one Idaho “group return” for the entire unitary group. Group returns don’t ignore the corporate identities of the individual corporations. Each corporation is considered a taxpayer even though it’s part of a unitary group and regardless of whether a group return is filed or each corporation files its own Idaho income tax return.

Idaho returns must include copies of the federal returns and spreadsheets detailing the information identified in the following table:

ItemIf Filing a Group ReturnIf Filing Separate Returns for Each Idaho Filer

  • Federal taxable income detail

  • Intercompany eliminations

  • State adjustments to federal taxable income

  • Income/loss allocated outside Idaho


Forms 41 and 42 Include total amounts for the combined group – provide by-company spreadsheets for each corporation in the unitary groupSame as if filing a group return

  • Income/loss allocated to Idaho

  • Idaho taxable income

  • Idaho income tax

  • Idaho net operating loss deduction

  • Idaho credits earned/allowed

  • Permanent Building Fund tax

  • Total tax due


Form 41 includes total amounts for all Idaho filers – provide spreadsheets for each Idaho filerForm 41 includes amounts only for filing corporation – provide spreadsheets for each filing corporation

  • Idaho apportionment factor


Form 42 includes total amounts for all Idaho filers – provide Form 42A By-Company Apportionment Factor Details listing all corporations listed as transacting in Idaho.Form 42 includes amounts only for filing corporation – provide Form 42A By-Company Apportionment Factor Details listing all corporations listed as transacting in Idaho.