Form 42A
                              By-Company Apportionment Factor Details                                                           2024
                              Include with Idaho Form 42
Name as shown on return                                                                                              Federal Employer Identification Number (EIN)

                                                 Check if using three-factor apportionment
                                                                                               Idaho          Name   Name   Name
                                                                                               Combined
Idaho Property                                                                                  Corporation   EIN    EIN    EIN
(Owned Property at Original Cost)                                                              Total
Beginning of Year
1.  Inventories ...............................................................................
2.  Real and tangible personal property .......................................
Ending of Year
3.  Inventories ...............................................................................
4.  Real and tangible personal property .......................................
5.  Total of lines 1 through 4 .........................................................
6.  Average. Line 5 divided by 2 ...................................................
7.  Rented property (capitalized at 8 times rents paid) .................
8.  Total property. Add lines 6 and 7 .............................................
9.  Idaho property percentage. Line 8 divided by 
    Idaho Form 42, line 8, Total column. Compute 
    percentage to four decimal places ...........................................                           %      %      %                                          %
Idaho Sales (Gross Receipts) 
10. Gross sales, less returns and allowances ...............................
11. Sales delivered or shipped to Idaho purchasers .....................
12. Idaho “throwback” sales ..........................................................
13. Sales of services .....................................................................
14. Other business gross receipts .................................................
15. Total gross receipts. Add lines 11 through 14 ..........................
16. Idaho sales percentage. Line 15 divided by 
    Idaho Form 42, line 15, Total column. Compute 
    percentage to four decimal places ...........................................                           %      %      %                                          %
Idaho Payroll
17. Total wages and salaries .........................................................
18. Idaho payroll percentage. Line 17 divided by 
    Idaho Form 42, line 18, Total column. Compute 
    percentage to four decimal places ...........................................                           %      %      %                                          %
19. Total percentage. Add lines 9, 16, and 18 .............................                                 %      %      %                                          %
20. Idaho apportionment factor.................................. ...............                            %      %      %                                          %
EFO00334   07-10-2024                                                                                                           Page                             1 of

                                                                                                                  Form 42A     2024     (continued)
Name as shown on return                                                                                      Federal Employer Identification Number (EIN)

                        Check if using three-factor apportionment
                                                                                               Name   Name   Name   Name

Idaho Property                                                                                 EIN    EIN    EIN    EIN
(Owned Property at Original Cost)
Beginning of Year
1.  Inventories ...............................................................................
2.  Real and tangible personal property .......................................
Ending of Year
3.  Inventories ...............................................................................
4.  Real and tangible personal property .......................................
5.  Total of lines 1 through 4 .........................................................
6.  Average. Line 5 divided by 2 ...................................................
7.  Rented property (capitalized at 8 times rents paid) .................
8.  Total property. Add lines 6 and 7 .............................................
9.  Idaho property percentage. Line 8 divided by 
    Idaho Form 42, line 8, Total column. Compute 
    percentage to four decimal places ...........................................                   %      %      %                                        %
Idaho Sales (Gross Receipts) 
10. Gross sales, less returns and allowances ...............................
11. Sales delivered or shipped to Idaho purchasers .....................
12. Idaho “throwback” sales ..........................................................
13. Sales of services .....................................................................
14. Other business gross receipts .................................................
15. Total gross receipts. Add lines 11 through 14 ..........................
16. Idaho sales percentage. Line 15 divided by 
    Idaho Form 42, line 15, Total column. Compute 
    percentage to four decimal places ...........................................                   %      %      %                                        %
Idaho Payroll
17. Total wages and salaries .........................................................
18. Idaho payroll percentage. Line 17 divided by 
    Idaho Form 42, line 18, Total column. Compute 
    percentage to four decimal places ...........................................                   %      %      %                                        %
19. Total percentage. Add lines 9, 16, and 18 .............................                         %      %      %                                        %
20. Idaho apportionment factor .................................................                    %      %      %                                        %
EFO00334   07-10-2024                                                                                                   Page                             of

                       Form 42A — Instructions
                                                                                    2024
                       By-Company Apportionment Factor Details

General Instructions                            The Idaho combined corporation total of 
Form 42A is a by-company breakout of the        Form 42A should be identical to the total of the 
numerators reported on Form 42 Part I.          Idaho column on Form 42. This amount should 
Apportionment Formula.                          include companies using both three-factor and 
                                                single-sales apportionment.
Any companies identified as “transacting 
business in Idaho” on Form 41A (column F) must  Line 20 Idaho Apportionment Factor.
be listed on Form 42A.                          For taxpayers using the three-factor apportionment 
                                                method, divide the total on line 19 by three. If any 
See Form 42 instructions for factor calculation of the factors don’t apply to your business, divide 
details.                                        the total on line 19 by the number of factors used. 
                                                For example, if your business has no employee 
Specific Instructions
                                                anywhere, your factor is reduced by one. For all 
Enter name and federal Employer Identification  other taxpayers, use the percentage on line 20. Add 
Number (EIN) for each company.                  each company’s Idaho percentage for the Idaho 
                                                Combined Corporation Total column.
Check the box for each company using 
three-factor apportionment.
Complete each field for each company 
transacting business in Idaho. The Idaho 
Combined Corporation Total column shouldn’t 
exceed the sum of all companies listed on 
Form 42A. 

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                       In the Boise area: (208) 334-7660 | Toll free: (800) 972-7660
                               Hearing impaired (TDD) (800) 377-3529
                                         tax.idaho.gov/contact
EIN00111 07-10-2024