IL‑990‑T Form Instructions 2025

Form IL‑990‑T is Illinois’ Exempt Organization Income and Replacement Tax Return used by exempt organizations (such as charities, employee trusts, and other entities otherwise exempt from income tax) to report unrelated business taxable income and compute Illinois replacement tax, income tax (if applicable), credits, surcharges, and the resulting refund or balance due for a given tax year; it is due on or before the 15th day of the 5th month after the close of the organization’s tax year (4th month for employee trusts), applies to tax years ending on or after December 31, 2024 and before December 31, 2025, requires whole‑dollar reporting, and generally must include a copy of federal Form 990‑T when unrelated business income is present.

How To File IL‑990‑T

File IL‑990‑T electronically when possible or by mail to the Illinois Department of Revenue using the addresses on the form; if a payment is enclosed, mail to P.O. Box 19053, Springfield, IL 62794‑9053, and if no payment is enclosed, mail to P.O. Box 19009, Springfield, IL 62794‑9009, ensuring payment vouchers (Form IL‑990‑T‑V) are attached when paying by check or money order and that the FEIN, tax year ending, and “IL‑990‑T‑V” are printed on the payment.

When IL‑990‑T is Due

The return is due by the 15th day of the 5th month after the close of the tax year (or 4th month for employee trusts); for fiscal filers not on the 2024 calendar, enter beginning and ending dates in the top date fields and confirm the period falls between December 31, 2024 and December 31, 2025 to use this revision.

How to Complete IL‑990‑T

This section follows the form from top to bottom, Step 1 through Step 7, including every checkbox and line.

Header And Filing Period

Enter fiscal tax year beginning and ending dates if not calendar year 2024, ensuring the period ends on or after December 31, 2024 and before December 31, 2025; use whole dollars throughout and attach federal Form 990‑T when required.

Step 1: Identify Your Exempt Organization

Line A — Enter complete legal business name; check the adjacent box if there has been a name change.
Line B — Enter mailing address, including C/O if applicable, city, state, and ZIP Code.
Line C — Check “First return” if this is your first IL‑990‑T; check “Final return” if terminating and enter termination date in mm/dd/yyyy.
Box A (apportionment choice) — Check if all of Line 3 income is derived inside Illinois only, or if you are an Illinois resident trust; then carry Step 2, Line 3 directly to Step 4, Line 12 and leave Step 3 Lines 4–11 blank.
Box B (apportionment required) — Check if any portion of Line 3 is derived outside Illinois; you must complete all lines of Step 3 and cannot leave Lines 6–8 blank.
Box D — Enter FEIN.
Box E — Check if taxed as a corporation.
Box F — Check if taxed as a trust.
Box G — Provide the nature of your unrelated trade or business.
Box H — Check if attaching Schedule 1299‑D (Income Tax Credits).
Box I — Enter NAICS code, if applicable.
Box J — Check if a 52/53‑week filer.
Payment box (top right) — Enter the amount you are paying, if any, and physically attach payment and Form IL‑990‑T‑V where indicated.

Step 2: Figure Your Base Income Or Loss

Line 1 — Enter unrelated business taxable income or loss from federal Form 990‑T; attach a copy of federal Form 990‑T.
Line 2 — Enter Illinois income and replacement tax and surcharge that were deducted in arriving at Line 1.
Line 3 — Base income or loss: add Lines 1 and 2.

Step 3: Figure Your Income Allocable To Illinois (Complete Only If Step 1 Box B Is Checked)

Line 4 — Enter business income or loss included in Line 3 from non‑unitary partnerships, partnerships included on a Schedule UB, S corporations, trusts, or estates.
Line 5 — Business income or loss: subtract Line 4 from Line 3.
Line 6 — Total sales everywhere (cannot be negative).
Line 7 — Total sales inside Illinois (cannot be negative).
Line 8 — Apportionment factor: divide Line 7 by Line 6 and round to six decimal places.
Line 9 — Business income or loss apportionable to Illinois: multiply Line 5 by Line 8.
Line 10 — Business income or loss apportionable to Illinois from non‑unitary partnerships, partnerships included on a Schedule UB, S corporations, trusts, or estates.
Line 11 — Base income or loss allocable to Illinois: add Lines 9 and 10.

Step 4: Figure Your Net Replacement Tax

Line 12 — Net income or loss from Line 3 (if Step 1 Box A) or Line 11 (if Step 1 Box B).
Line 13 — Replacement tax: corporations multiply Line 12 by 2.5% (0.025); trusts multiply by 1.5% (0.015).
Line 14 — Recapture of investment credits: attach Schedule 4255.
Line 15 — Replacement tax before investment credits: add Lines 13 and 14.
Line 16 — Investment credits: attach Form IL‑477.
Line 17 — Net replacement tax: subtract Line 16 from Line 15; if negative, enter zero.

Step 5: Figure Your Net Income Tax

Line 18 — Net income or loss from Line 12.
Line 19 — Income tax (see instructions referenced by the form); compute per applicable rules.
Line 20 — Recapture of investment credits: attach Schedule 4255.
Line 21 — Income tax before credits: add Lines 19 and 20.
Line 22 — Income tax credits: attach Schedule 1299‑D.
Line 23 — Net income tax: subtract Line 22 from Line 21; if negative, enter zero.

Step 6: Figure Your Refund Or Balance Due

Line 24 — Net replacement tax from Line 17.
Line 25 — Net income tax from Line 23.
Line 26 — Compassionate Use of Medical Cannabis Program Act surcharge (see instructions).
Line 27 — Sale of assets by gaming licensee surcharge (see instructions).
Line 28 — Total net income and replacement taxes and surcharges: add Lines 24, 25, 26, and 27.
Line 29a — Credits from previous overpayments.
Line 29b — Total payments made before the date this return is filed.
Line 29c — Pass‑through withholding reported to you on Schedule(s) K‑1‑P or K‑1‑T; attach those schedules.
Line 29d — Pass‑through entity tax credit reported to you; attach Schedule(s) K‑1‑P or K‑1‑T.
Line 29e — Illinois income tax withholding; attach Form(s) W‑2G.
Line 30 — Total payments: add Lines 29a through 29e.
Line 31 — Overpayment: if Line 30 > Line 28, subtract Line 28 from Line 30.
Line 32 — Amount to be credited forward (see instructions); check the box and attach a detailed statement if carrying forward to a different FEIN.
Line 33 — Refund: subtract Line 32 from Line 31; this is the refund amount.
Line 34 — Direct deposit: enter Routing Number, select Checking or Savings, and enter Account Number for refund direct deposit.
Line 35 — Tax due: if Line 28 > Line 30, subtract Line 30 from Line 28; this is the amount you owe.

Payment guidance: If Line 35 shows tax due, pay electronically at Tax.Illinois.gov; if mailing payment, complete Form IL‑990‑T‑V, make check or money order payable to “Illinois Department of Revenue,” write FEIN, tax year ending, and “IL‑990‑T‑V” on the payment, attach voucher and payment to the front of the return, and enter the payment amount at the top of Page 1.

Step 7: Sign Below

An authorized officer must sign under penalties of perjury, dating the return and providing title and phone; optionally check the box authorizing the Department to discuss the return with the paid preparer listed, and complete paid preparer information (name, signature, date, PTIN, firm’s FEIN, address, and phone), marking “self‑employed” if applicable; mail to the correct P.O. Box based on whether a payment is enclosed.

Practical Filing Tips

Attach federal Form 990‑T whenever Line 1 reflects unrelated business taxable income, and include all referenced Illinois schedules (4255, 1299‑D, IL‑477, K‑1‑P, K‑1‑T, W‑2G) as applicable to avoid processing delays and notices.
If all base income is Illinois‑sourced (or you’re an Illinois resident trust), elect Box A and skip apportionment; otherwise, elect Box B and complete Step 3 including Lines 6–8 to compute your apportionment factor to six decimal places.
For refunds, provide accurate bank routing and account numbers in Step 6, Line 34 to speed direct deposit; for credits forward, attach the required statement if the FEIN receiving the credit differs.