Schedule M: Other Additions and Subtractions (for businesses) (2025)
Illinois · Illinois DOR · Used for tax years 2025
Illinois Schedule M reports other additions and subtractions for businesses for tax years ending on or after December 31, 2025. It calculates totals to carry to Form IL-1120, IL-1120-ST, IL-1065, or IL-1041 and is attached to that return.
Who files this form
Schedule M reports other additions and subtractions for businesses. The form directs filers to attach it to Form IL-1120, IL-1120-ST, IL-1065, or IL-1041.
The 2025 version is for tax years ending on or after December 31, 2025. The form does not state a separate filing threshold.
What you'll need
- Your name as shown on your tax return, federal employer identification number (FEIN), and tax year ending month and year.
- Your Form IL-1120, IL-1120-ST, IL-1065, or IL-1041, to which Schedule M must be attached.
- If claiming interest subtractions on Line 20, a copy of the statement identifying the payer and the interest amount for each obligation. Attach this statement.
- If reporting unused patronage or nonpatronage losses on Line 34, Schedule INL amounts and the year you first made the Schedule INL, Step 2, Line 1a election. This line is for Form IL-1120 filers only.
How to file
- Enter your identifying information in Step 1.
- Figure additions in Step 2. Add Lines 1 through 10 and enter the total on Line 11.
- Figure subtractions in Step 3. Enter total subtractions on Line 40.
- Transfer the totals to your return:
| Return | Line 11 additions go to | Line 40 subtractions go to |
| --- | --- | --- |
| IL-1120 | Line 8 | Line 21 |
| IL-1120-ST | Line 21 | Line 33 |
| IL-1065 | Line 22 | Line 33 |
| IL-1041 | Line 10 | Line 24 |
Attach Schedule M to your return. The supplied form does not give a mailing address or e-filing instructions.
Common mistakes
- Using Line 39 without IDOR instructions. Do not enter an amount on Line 39 unless the Illinois Department of Revenue (IDOR) instructs you to do so. An unapproved subtraction may cause processing delays.
- Leaving out required information. The form warns that disclosure of the requested information is required and that failure to provide it could result in a penalty.
Questions people ask
Can every filer use every line?
No. Some lines are limited to particular return types. For example, Lines 5 and 6 are for IL-1041 filers only, Line 9 is for IL-1120 filers only, and Line 25 is for IL-1120-ST filers only.
Can I subtract interest from any Illinois state or local government obligation?
Line 20 lists specific eligible obligations. The interest must be included in Illinois income, and you must attach a statement identifying the payer and interest amount for each obligation.
Where do I report a federally taxed Illinois state refund from a prior year?
Report it on Line 24.
Can I use Line 39 for a subtraction that does not fit elsewhere?
Only if IDOR instructs you to do so. Line 39 is for eligible Publication 101 subtractions not taken anywhere else, and you must identify each item.