Schedule 1299-D: Income Tax Credits (for corporations and fiduciaries) (2025)
Illinois · Illinois DOR · Used for tax years 2025
Illinois Schedule 1299-D reports income tax credits for corporations and fiduciaries and calculates the amount that may be claimed for the current year. It includes credits earned or received during the year and credits carried into the year, and attaches to Form IL-1120, IL-1041
Who files this form
Schedule 1299-D is for corporations and fiduciaries claiming income tax credits. Attach it to Form IL-1120, IL-1041, or IL-990-T.
The 2025 schedule applies to tax years ending on or after December 31, 2025.
What you'll need
Have these forms and details available, as applicable:
- Your Form IL-1120, IL-1041, or IL-990-T, including your name, federal employer identification number (FEIN), and income tax amount.
- Schedule 1299-I, Income Tax Credits Information and Worksheets, and the Schedule 1299-D Instructions. The form directs you to these for help completing the schedule.
- The amount of credit available to carry into this tax year.
- Current-year credit details, including credit codes, expiration dates, dates earned, certificate numbers, and unitary member FEINs, as applicable.
- Schedule K-1-P information for distributive share credits and amounts of any transferred credits.
- Form IL-1041, Schedule CR, if you are an IL-1041 filer claiming a credit for income tax paid to another state.
How to file
Attach Schedule 1299-D to your Form IL-1120, IL-1041, or IL-990-T. The supplied form does not give a mailing address or e-filing directions.
- Enter your name as shown on your return, your FEIN, and your tax year ending month and year.
- Complete Step 1 only if you earned the Research and Development credit during the current tax year.
- Complete Step 3 before Step 2. List credits earned or received during the current tax year, even if you are not using them.
- Use Step 2 to calculate the credit you may claim. Transfer Line 10 to Form IL-1120, Step 7, Line 48; Form IL-1041, Step 6, Line 46; or Form IL-990-T, Step 5, Line 22.
Common mistakes
- Leaving out required information: The form warns that failure to provide information could result in a penalty.
- Not rounding amounts: Round all figures to whole dollars.
- Completing Step 2 too soon: Complete Step 3 first.
- Listing prior-year credits in Step 3 or omitting unused current-year credits: Step 3 is only for credits earned or received during the current tax year, including credits you are not using.
- Separating credits that should be combined: Combine credits with the same code on one line, except when earned by different unitary group members or associated with different certificate numbers.
- Handling extra credits incorrectly: If you need more lines, attach a separate schedule in the same format with all required information. Complete Step 3, Line 35, Column I only on Schedule 1299-D.
Questions people ask
Do I need to complete the Research and Development worksheet?
Complete Step 1 only if you earned this credit during the current tax year. Start with the amounts from Schedule 1299-I, Line 6 of the Research and Development Worksheet.
How much credit can I claim this year?
Step 2, Line 10 is the lesser of Line 6, your total available credits, or Line 9, your income tax after subtracting the applicable credit for income tax paid to another state. If that subtraction produces zero or a negative amount, enter zero on Line 9.
Do I list current-year credits that I am not using?
Yes. Step 3 requires all credits earned or received during the current tax year, even if they are not being used.
Where can I calculate my credit carryforward for next year?
The form says you may use the worksheet in the Schedule 1299-D Instructions to determine your credit carryforward for the next tax year.