Schedule 1299-D is an Illinois Department of Revenue form titled “Income Tax Credits (for Corporations and Fiduciaries)”. It’s used by corporations, trusts, and other fiduciaries to report, calculate, and claim various Illinois income tax credits. The schedule applies to tax years ending on or after December 31, 2024, and must be attached to Form IL-1120, Form IL-1041, or Form IL-990-T depending on your type of filer.
Essentially, Schedule 1299-D helps you determine how much credit your business or fiduciary entity can apply to reduce its Illinois income tax liability. It also allows you to record credits carried forward from previous years, current-year credits earned (such as Research and Development), and credits transferred or distributed from other entities. Every figure should be entered in whole dollars, and you’re required to provide this information by law. Failure to file it correctly may lead to penalties. If you have more credits than the form’s lines allow, you can attach a separate page in the same format.
How To File Schedule 1299-D
- Download and Complete the Form
Obtain the official Schedule 1299-D from the Illinois Department of Revenue website. Ensure you’re using the R-12/24 version or a newer one. - Attach It to the Correct Return
- Corporations attach it to Form IL-1120.
- Fiduciaries (trusts, estates) attach it to Form IL-1041.
- Exempt organizations with unrelated business income attach it to Form IL-990-T.
- Provide Identification Information
Enter the name exactly as shown on your return and your Federal Employer Identification Number (FEIN). Fill in your tax year ending month and year. - Complete Steps 1–3 in Order
- Step 1 applies only if you earned a Research and Development credit this year.
- Step 3 must be filled before Step 2, since Step 2 depends on totals from Step 3.
- Round all figures to whole dollars.
How to Complete Schedule 1299-D
Step 1: Worksheet – Research and Development Credit
(Complete this only if you earned R&D credits in the current year.)
Line 1:
Enter the amounts from Schedule 1299-I, Line 6 of the R&D Worksheet.
- Column A = Base period average expenses.
- Column B = Current year’s qualifying expenses.
Line 2:
Subtract Column A from Column B. If the result is negative, enter 0.
Line 3:
Multiply the Line 2 result by 6.5% (0.065). This gives your R&D credit.
Enter this amount here and in Step 3, Column F on the line showing Credit Code 5340.
Step 2: Calculate Your Credit for the Current Year
(You’ll fill this out after completing Step 3.)
Line 4:
Enter any credit carried forward into this tax year. (See the instructions accompanying the form for how to determine this.)
Line 5:
Enter the total from Step 3, Line 35, Column I — the sum of all current-year credits.
Line 6:
Add Lines 4 and 5 to find the total available credit.
Line 7:
Enter your Illinois income tax from the relevant form:
- Form IL-1120 → Step 7, Line 47
- Form IL-1041 → Step 6, Line 44
- Form IL-990-T → Step 5, Line 21
Line 8:
Form IL-1041 filers only — enter the Credit for Income Tax Paid to Another State from Schedule CR, Step 5, Line 59.
All other filers enter 0.
Line 9:
Subtract Line 8 from Line 7. If zero or negative, enter 0.
Line 10:
Enter the lesser of Line 6 or Line 9.
This is the amount of credit you can claim this year.
Also report this same figure on your main tax form:
- IL-1120 → Step 7, Line 48
- IL-1041 → Step 6, Line 46
- IL-990-T → Step 5, Line 22.
Step 3: Enter Your Current Credits
(This step must be completed before Step 2.)
List only credits earned or received in the current tax year, even if you’re not using them now. If you have credits of the same type, combine them on one line unless they belong to different unitary group members or have separate certificate numbers. Use the worksheet in your official instructions to track carryforwards for the next year.
Each line (11–34) of Step 3 includes the following columns:
| Column | What To Enter |
|---|---|
| A – Expiration Date (YYYY-MM) | The month and year when the credit expires. |
| B – Credit Code | The code assigned to the type of credit (e.g., 5340 for R&D). |
| C – Credit Earned (YYYY-MM) | The month and year when you earned the credit. |
| D – Unitary Member FEIN | The federal identification number of the unitary group member (if applicable). |
| E – Certificate Number | Enter any certificate number associated with the credit. |
| F – Credit Amount Earned | The dollar amount of the credit earned this year. |
| G – Distributive Share Credit from K-1-P | Enter the share passed to you from a partnership or S-corporation. |
| H – Transferred Credit Amount | Enter credits transferred to you by another entity. |
| I – Total Credits (F + G + H) | Add the previous three columns to determine the total for that line. |
Lines 11–34:
Use as many of these lines as needed to list your individual credits.
Line 35:
Add together all totals from Column I (Lines 11–34) and enter the sum here.
Then carry this amount to Step 2, Line 5.
Key Tips for Accurate Filing
- Round to Whole Dollars: Do not include cents.
- Attach Supporting Schedules: If you exceed the provided lines, include an additional sheet with the same format.
- Cross-Check Codes: Ensure each credit’s code and certificate match official listings.
- File Electronically: The form is electronic only—no paper submissions are accepted.
- Keep Documentation: Retain copies of certificates, K-1-P forms, and credit worksheets for audit verification.