Idaho Administrative Code
Title IDAPA 35 - Tax Commission, State
Rule 35.01.01 - INCOME TAX ADMINISTRATIVE RULES
Section 35.01.01.450 - APPORTIONMENT FORMULA

01. Apportionment Factors. All of a taxpayer's apportionable income is to be apportioned to Idaho using the apportionment formula set forth in Section 63-3027(10), Idaho Code. Generally, a taxpayer's apportionment formula consists of the sales factor only. Pursuant to Section 63-3027(10)(b), however, certain taxpayers may elect an apportionment formula that includes the property factor, the payroll factor, and the sales factor. See Rules 460 through 559 of these rules for general rules applicable to these factors. See Rules 560 through 599 of these rules for special rules and exceptions to the apportionment formula. The denominator of each factor may not exceed the sum of the numerators of that factor.

02. Intercompany Transactions. Intercompany transactions are to be eliminated to the extent necessary to properly compute the numerators and the denominators of the apportionment factors of a combined group. The apportionment factor computation may not include property, payroll, or receipts of any affiliated corporation unless its income is included in the combined report.

03. Rounding. The individual factors and the average apportionment factor is to be calculated six (6) digits to the right of the decimal point. If the seventh digit is five (5) or greater, the sixth digit is rounded to the next higher number. If the seventh digit is less than five (5), the sixth digit remains unchanged and any digits remaining to its right are dropped.

04. Verification of Factors. The taxpayer is to make available the fifty-one (51) state apportionment factor detail when requested by the Tax Commission. Failure to do so may justify the imposition of the negligence penalty provided by Section 63-3046(a), Idaho Code.