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2023 Corporate Income Tax Forms

 

Name Description
IL-1120

Instructions

Corporation Income and Replacement Tax Return
IL-1120-V  

Payment Voucher for Corporation Income and Replacement Tax

To make a return or extension payment, use this voucher and Appendix A of Form IL-1120 Instructions.
To make an estimated payment, use this voucher and Appendix B of Form IL-1120 Instructions.

Important: Ensure the proper month and year of the filing period you wish to make a payment for is entered on the "Tax year ending" lines of the voucher.

​IL-1120-X
Instructions
Amended Corporation Income and Replacement Tax Return
IL-1120-X-V  

Payment Voucher for Amended Corporation Income and Replacement Tax

Important: Ensure the proper month and year of the filing period you wish to make a payment for is entered on the "Tax year ending" lines of the voucher.

IL-477 Instructions Replacement Tax Investment Credits
IL-2220 Instructions Computation of Penalties for Businesses
IL-4562

Instructions

Special Depreciation
Schedule INL Instructions Illinois Net Loss Adjustments for Cooperatives and REMIC Owners
Schedule INS Instructions Tax for Foreign Insurers
Schedule J Instructions Foreign Dividends
Schedule M Instructions Other Additions and Subtractions (for businesses)
Schedule NB Instructions Nonbusiness Income
Schedule NLD Instructions Illinois Net Loss Deduction
Schedule UB
2/23/24 - Updated Step 2, Line 25, to reflect 
federal Form 1120, Line 25 (Energy efficient
commercial buildings deduction).
Instructions Combined Apportionment for Unitary Business Group
Schedule UB/INS Instructions Tax for a Unitary Business Group with Foreign Insurer Members
Schedule UB/NLD Instructions Unitary Illinois Net Loss Deduction
Schedule 80/20 Instructions Related-Party Expenses
Schedule 1299-B Instructions
River Edge Redevelopment Zone or Foreign Trade Zone (or sub-zone) Subtractions (for corporations and fiduciaries)
Schedule 1299-D

Instructions

Income Tax Credits (for corporations and fiduciaries)
Schedule 1299-I   Income Tax Credits Information and Worksheets
Schedule 4255

Instructions

 
Subgroup Schedule (UB) Instructions
Subgroup Schedule