IDAPA 35.01.01.450 — APPORTIONMENT FORMULA (RULE 450)

Section 63-3027(10), Idaho Code
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.
(4-6-23)
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.
(4-6-23)
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.
(4-6-23)
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.
(4-6-23)