IL-990-T-X: Amended Exempt Organization Income and Replacement Tax Return (2025)
Illinois · Illinois DOR · Used for tax years 2025
Form IL-990-T-X is the Illinois Amended Exempt Organization Income and Replacement Tax Return. It reports corrected income, taxes, credits, and payments to figure a refund or additional tax due.
Who files this form
Form IL-990-T-X is for exempt organizations amending an Illinois Exempt Organization Income and Replacement Tax Return.
The 2025 version is for tax years ending on or after December 31, 2025. Do not use it to amend a return for a tax year ending before that date.
Identify whether the amendment involves a state or federal change. For a federal change, indicate whether it is partially agreed or finalized, enter the finalization date, and attach the federal finalization.
What you'll need
Have these records and details ready:
- Your organization's legal name, mailing address, FEIN, and the beginning and ending dates of the tax year being amended.
- The amounts most recently reported or adjusted, along with the corrected amounts.
- Unrelated business taxable income or loss from federal Form 990-T.
- An explanation of the changes. Attach a separate sheet if needed.
- Records of payments, previously paid penalty and interest, and earlier overpayments for the year being amended.
Attach these documents when they apply:
- Federal finalization for a federal change.
- Schedule 4255 for recapture of investment credits.
- Form IL-477 for investment credits.
- Schedule 1299-D for income tax credits.
- Schedules K-1-P or K-1-T for pass-through withholding or pass-through entity tax credits reported to you.
- Forms W-2G for Illinois income tax withholding.
- A detailed statement if an overpayment carryforward is going to a different FEIN.
- Form IL-990-T-X-V and your payment if you owe tax on Line 38.
How to file
- Enter the tax year you are amending and your organization's identifying information. Explain the changes.
- Enter the amounts most recently reported or adjusted in Column A and the corrected amounts in Column B. Use whole dollars for dollar amounts.
- Complete the applicable income, tax, and payment calculations to figure your refund or balance due. Include the required attachments.
- Have an authorized officer sign and date the return and provide their title and phone number.
- Mail the return to:
Illinois Department of Revenue
PO Box 19016
Springfield, IL 62794-9016
If you owe tax on Line 38, complete Form IL-990-T-X-V. Make your check or money order payable to “Illinois Department of Revenue” and write your FEIN, tax year ending, and “IL-990-T-X-V” on it. Attach the voucher and payment to the front of the return, and enter the payment amount at the top of Page 1.
Common mistakes
- Using the wrong year's form: Do not use this version for tax years ending before December 31, 2025.
- Completing Step 3 when it does not apply: If the Line 3 amount is derived only inside Illinois, or you are an Illinois resident trust, check box A above Step 3, carry Line 3 to Line 12, and leave Lines 4 through 11 blank.
- Leaving apportionment lines blank: If any portion of the Line 3 amount is derived outside Illinois, check box B above Step 3 and complete all lines in Step 3. Do not leave Lines 6 through 8 blank.
- Entering negative sales amounts: Lines 6 and 7 cannot be negative. Round the Line 8 apportionment factor to six decimal places.
- Entering negative net tax: If the calculation for Line 17 or Line 23 is negative, enter zero.
- Omitting required information: The form warns that failure to provide required information could result in a penalty.
Questions people ask
Do I need to explain the changes?
Yes. The form asks you to explain the changes on the return. Attach a separate sheet if necessary.
What replacement tax rate does the form use?
For Line 13, corporations multiply Line 12 by 2.5% (.025), and trusts multiply Line 12 by 1.5% (.015).
Can I carry an overpayment forward instead of receiving all of it as a refund?
The form provides Line 36 for the portion of your Line 35 overpayment to be credited forward. Line 37 is the remaining refund. If the carryforward is going to a different FEIN, check the box and attach a detailed statement.
How will I learn about additional penalty and interest?
The form states that you will be sent a bill for any additional penalty and interest.