Form 42A
                              By-Company Apportionment Factor Details                                                           2023
                              Include with Idaho Form 42
Name as shown on return                                                                                              Federal Employer Identification Number (FEIN)

                                              Check if using three-factor apportionment
                                                                                               Idaho          Name   Name   Name
                                                                                               Combined
Idaho Property                                                                                  Corporation   FEIN   FEIN   FEIN
(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   08-31-2023                                                                                                           Page                              1 of

                                                                                                                  Form 42A     2023     (continued)
Name as shown on return                                                                                      Federal Employer Identification Number (FEIN)

                        Check if using three factor apportionment
                                                                                               Name   Name   Name   Name

Idaho Property                                                                                 FEIN   FEIN   FEIN   FEIN
(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   08-31-2023                                                                                                   Page                              of

                       Form 42A — Instructions
                                                                                    2023
                       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 10 on Form 42A is for everywhere sales use 
be listed on Form 42A.                          only. Don’t enter an amount on Form 42A.

See Form 42 instructions for factor calculation Line 20 Idaho Apportionment Factor.
details.                                        To calculate each company’s Idaho apportionment 
                                                factor: 
Specific Instructions
                                                Divide line 19 by the number of factors for each 
Enter name and federal Employer Identification  company. Add each company’s Idaho percentage 
Number (EIN) for each company.                  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. 

                                                Contact us:
                       In the Boise area: (208) 334-7660 | Toll free: (800) 972-7660
                               Hearing impaired (TDD) (800) 377-3529
                                         tax.idaho.gov/contact
EIN00111 08-31-2023