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      Illinois Department of Revenue                                                  Use for tax years ending on or 
                                                                                      after December 31, 2023, and 
                                                                                      before December 31, 2024.
      IL-1120-ST-X Instructions                                                                                               2023
                                           General Information
Who must file Form IL-1120-ST-X?                                        • a copy of your federal audit report (signed and dated by a 
                                                                          federal auditor);
You should file Form IL-1120-ST-X, Amended Small Business 
Corporation Replacement Tax Return, if you are amending a               • an IRS account transcript; or
previously filed, processable Form IL-1120-ST, Small Business           • a federal refund check.
Corporation Replacement Tax Return, for a tax year ending on or                Acknowledgement that the IRS received your amended 
after December 31, 2006. Your change can occur from a state or          return is not acceptable proof of federal finalization.
federal change that affects items used to compute your Illinois net     If your federal change decreases the tax due to Illinois and 
income, net loss, or credits, such as                                   you are entitled to a refund or credit carryforward, you must file 
• an amendment of your federal income tax return,                       Form IL-1120-ST-X within two years plus 120 days of federal 
• an adjustment made by the Internal Revenue Service (IRS),             finalization. 
  or                                                                    If your federal change increases the tax due to Illinois, you must file 
• any other recomputation or redetermination.                           Form IL-1120-ST-X and pay any additional tax within 120 days of 
A separate amended return must be filed for each tax year you need      IRS partial agreement or finalization. In order to avoid late payment 
to amend.                                                               penalties, you must pay any additional tax to IDOR and attach proof 
                                                                        of the federal finalization date, showing the change was reported to 
What if I need to change my return before the                           Illinois within 120 days of IRS acceptance, or you may be assessed a 
extended due date expires?                                              late-payment penalty.
If you filed your original Form IL-1120-ST and a state or federal              If you fail to notify us of your change by filing Form 
correction or change needs to be made before the extended due           IL-1120-ST-X, we may issue a notice of deficiency at any time. Once 
date expires (see the instructions of your original return), you should you file your change, we may issue a notice of deficiency within two 
file Form IL-1120-ST-X. Due to the automatic extension, any return      years.
filed after the original return and on or before the extended due date 
                                                                        What if I am amending my return due to multiple 
will be treated as the original return.
If you are filing Form IL-1120-ST-X to change the election on your      federal adjustments?
original return to treat all income other than compensation as          If you are amending your original Form IL-1120-ST due to multiple 
business income, check the box in Step 1, Line R, and provide a         federal adjustments that were finalized on different dates, then 
written explanation indicating the change to your election in the       you must complete separate amended Illinois returns for each 
“Explain the changes on this return” area.                              federal finalization date. For example, if you receive a 2023 return 
                                                                        adjustment from the IRS on July 10, 2024, and in August 2024, you 
How long do I have to amend my return?                                  amend your U.S. Form 1120-S and receive federal finalization on 
The amount of time you have to amend your return depends on             October 22, 2024, then you must submit one Form IL-1120-ST-X for 
whether your Form IL-1120-ST-X is being filed to report a state or      the July 10, 2024, adjustments and a separate Form IL-1120-ST-X 
federal change.                                                         for the October 22, 2024, adjustments. Failure to file separate 
       If an amended return claiming a credit or refund is filed        amended returns for each federal finalization date may result in the 
within six months of the expiration of the statute of limitations, then denial of the entire claim, a delay in processing, or the assessment of 
the statute of limitations will automatically be extended an additional penalty and interest. 
six months for issuing an assessment of additional tax due.                    Proof of federal finalization must be attached to your 
State change - If your change creates or increases the Illinois net     amended return before the return will be processed.
loss for the year, you must file Form IL-1120-ST-X showing the          What if my amended return involves unitary 
increase in order to carry the increased loss amount to another year.
                                                                        filing?
If your change decreases the tax due to Illinois and you are entitled 
                                                                        If you are amending your original
to a refund or credit carryforward, you must file Form IL-1120-ST-X 
                                                                        • non-unitary Form IL-1120-ST to be included in an existing 
within
                                                                          unitary group, you must file an amended Form IL-1120-ST-X, 
•   three years after the due date of the return (including               following the line by line instructions provided for 
  extensions),                                                            Form IL-1120-ST, Schedule UB, Combined Apportionment for 
• three years after the date your original return was filed, or           Unitary Business Groups, and Subgroup Schedule, for the tax 
• one year after the date your Illinois tax was paid, whichever           year you are amending. In addition,
  is latest.                                                              —  any combined return filed by the combined group on 
If your change increases the tax due to Illinois, you should file 
                                                                               Form IL-1120 must also be amended to include your 
Form IL-1120-ST-X and pay the tax, penalty, and interest promptly.
                                                                               information, and
Federal change - Do not file this amended return until you                —  each member that filed a separate unitary return must file 
receive a federal finalization notification from the IRS stating that          an amended return to include your information.
they have accepted your change, either by paying a refund, or by        • unitary Form IL-1120-ST to report a state or federal change to 
final assessment, agreement, or judgment. In order to process an          your unitary income, any combined return filed by the group or 
amended return due to a federal change, the Illinois Department           separate unitary return may also need to be amended.
of Revenue (IDOR) requires proof of federal finalization. Proof of 
federal finalization includes one or more of the following:

IL-1120-ST-X Instructions (R-12/23)    Printed by the authority of the state of Illinois. - electronic only - one copy.        Page 1 of 6

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What if my amended return involves an Illinois                          Interest — The interest rate is the federal underpayment rate, which 
                                                                        is set by the IRS under Internal Revenue Code (IRC) Section 6621.
net loss deduction (NLD)?
                                                                           For more information about penalties and interest, see 
If you have an Illinois NLD carryover from any loss year ending on 
                                                                        Publication 103, Penalties and Interest for Illinois Taxes, available at 
or after December 31, 1986, it is subtracted from and limited to base 
                                                                        tax.illinois.gov.
income allocable to Illinois.
To determine your “Illinois net loss” start with your total unmodified               For amended tax returns filed on or after 
base income and apply all addition and subtraction modifications,       January 1, 2024, a late payment penalty will be assessed for any 
and all allocation and apportionment provisions.                        amended return not filed and the resulting liability not paid within 
                                                                        120 days of the federal change. See 35 ILCS 735/3-3(b-25) for more 
If you are carrying an Illinois NLD, you must complete and attach
                                                                        information.
Illinois Schedule NLD, Illinois Net Loss Deduction, and claim the
deduction on Step 7, Line 50. See Specific Instructions for Step 7,     What must I attach to my Form IL-1120-ST-X?
Line 50.                                                                This form must contain a complete explanation of the reasons 
Do not file Form IL-1120-ST-X to report an Illinois NLD carryforward    for filing the claim or amendment. You must attach proof of the 
until after you have filed the loss year Form IL-1120-ST,               federal finalization date and any schedules, forms, breakdowns, 
Form IL-1120-ST-X, or Form IL-843 (for tax years ending                 statements, or other documentation required to support your claim. 
prior to December 31, 2006) reporting the loss. When you                If Form IL-1120-ST-X is submitted without the proper attachments, it 
file Form IL-1120-ST-X, you must attach a completed Illinois            may be partially or totally denied.
Schedule NLD. Failure to attach the correct and completed schedule 
                                                                        Examples of federal finalization include a copy of one or more of the 
could result in partial or total denial of your claim.
                                                                        following items:
If you need more information, visit our website at tax.illinois.gov
and see the Schedule NLD instructions, or 86 Ill. Adm Code Sections     • your audit report from the IRS
100.2050 and 100.2300 through 100.2330.                                 • your federal record of account verifying your ordinary business 
                                                                          income
Who should sign the return?                                             If you are filing Form IL-1120-ST-X because
Your Form IL-1120-ST-X must be signed by the president, vice            •  you filed an amended federal return and your tax due to Illinois 
president, treasurer, or any other officer duly authorized to sign the    decreases, you must attach proof of the federal finalization 
return. If you paid someone (other than a regular, full-time employee     date, a copy of that federal return, plus any other related forms, 
of the taxpayer, such as a clerk, secretary, or bookkeeper) to prepare    schedules, or attachments, including a signed and dated copy 
your return, that individual must also provide a signature, date the      of any federal report of income tax examination changes, if 
return, enter the preparer tax identification number (PTIN) issued to     applicable.
them by the Internal Revenue Service, and provide their firm’s name,    •  you filed an amended federal return and your tax due to Illinois 
federal employer identification number (FEIN), address, and phone         increases, you must attach proof of the federal finalization 
number.                                                                   date, including a signed and dated copy of any federal report 
                                                                          of income tax examination changes, if applicable, showing 
Can a reasonable facsimile be used?                                       the change was reported to Illinois within 120 days of IRS 
In general, you must obtain and use forms prescribed by IDOR.             acceptance, or you may be assessed a late-payment penalty.
Separate statements not on forms provided or approved by 
IDOR will not be accepted and you will be asked for appropriate         •  of a change by the IRS, you must include all copies of the federal 
                                                                          examining officer’s reports, including preliminary, revised, 
documentation. Failure to comply with this requirement may 
                                                                          corrected, and superseding reports, and a signed and dated 
result in failure to file penalties, a delay in the processing of 
your return, or a delay in the generation of any overpayment.             copy of any federal report of income tax examination changes, if 
Additionally, failure to submit appropriate documentation when            applicable.
requested may result in a referral to our Audit Bureau for compliance   •  you copied information incorrectly from your U.S. Form 1120S 
action.                                                                   onto your Form IL-1120-ST, you must include a copy of your 
S corporations must complete Form IL-1120-ST-X. Do not send               U.S. Form 1120S.
a computer printout with line numbers and dollar amounts attached       •  of a change in, or audit of, another state’s tax return, you must 
to a blank copy of the return. Computer generated printouts are           include a copy of the other state’s corrected return or the 
not acceptable, even if they are in the same format as IDOR forms.        examining officer’s reports.
Computer generated forms from an IDOR-approved software                 •  of a change in the information reported on your Schedule B, 
developer are acceptable.                                                 Partners’ or Shareholders’ Information, you must include a 
                                                                          corrected Illinois Schedule B.
What are the penalties and interest?                                    •  of changes reported on a revised Schedule K-1-P or K-1-T (or 
Penalties — You will owe                                                  any equivalent document) you received, you must include a 
•  a late-filing penalty if you do not file a processable return by the   copy of the revised Schedule(s) K-1-P or K-1-T (or equivalent 
  extended due date;                                                      document). Do not attach copies of Schedule(s) K-1-P you 
•  a late-payment penalty if you do not pay the tax you owe by the        issued and which lists your name and federal employer 
  original due date of the return;                                        identification number (FEIN) in Step 1 of Schedule K-1-P.
• a late-payment penalty for underpayment of estimated tax if you       •  of changes, other than those described above, see Form 
  were required to make estimated tax payments and failed to do           IL-1120-ST Instructions and any schedules for the year you are 
  so, or failed to pay the required amount by the payment due date;       changing to determine what attachments you must provide.
•  a bad check penalty if your remittance is not honored by your 
  financial institution; 
•  a cost of collection fee if you do not pay the amount you owe 
  within 30 days of the date printed on your bill.
IL-1120-ST-X Instructions (R-12/23)                                                                                                Page 2 of 6

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Should I round? What if I need additional assistance or forms?
You must round the dollar amounts on Form IL-1120-ST-X to whole • For assistance, forms, or schedules, visit
dollar amounts. To do this, you should drop any amount less than our website at tax.illinois.gov or scan the
50 cents and increase any amount of 50 cents or more to the next QR code provided.
higher dollar. • Write us at:
ILLINOIS DEPARTMENT OF REVENUE
Where should I file? PO BOX 19001
Mail your Form IL-1120-ST-X to: SPRINGFIELD IL 62794-9001
ILLINOIS DEPARTMENT OF REVENUE • Call 1 800 732-8866 or 217 782-3336
PO BOX 19016 (TTY at 1 800 544-5304).
SPRINGFIELD IL 62794-9016 • Visit a taxpayer assistance office - 8:00 a.m. to 5:00 p.m.
(Springfield office) and 8:30 a.m. to 5:00 p.m. (all other offices),
Monday through Friday.

Specific Instructions
For instructions regarding completion of Steps 1 through 9, refer to J — Check this box if you are filing this amended return to report
the Form IL-1120-ST Instructions and schedules for the year being changes to your Illinois sales factor numerator due to the inclusion or
amended. exclusion of throwback sales.
Specific instructions for most of the lines are included. If a specific K — Check this box if you are filing this amended return to report
line is not referenced, follow the instructions on the form. changes to your Illinois sales factor numerator due to the inclusion or
Enter the tax year you are amending in the space provided at the top exclusion of double throwback sales.
of Form IL-1120-ST-X. L — Check this box if you are a 52/53 week filer. A 52/53 week
filer is a fiscal filer with a tax year that varies from 52 to 53 weeks
Step 1: Identify your small business because their tax year ends on the same day of the week instead
corporation of the last day of the month.
A — Type or print your legal business name. If you have a name M — Check this box if you elect to pay PTE tax in an amount equal
change from your original return, check the corresponding box. to 4.95 percent (0.0495) of the taxpayer’s calculated net income for
B — Type or print your mailing address. the taxable year on Line 61.
C — Check the box if you are filing this form only to report an N — Enter your entire federal employer identification number (FEIN).
increased net loss, you have no surcharges for Compassionate Use O — If you are a member of a unitary business group, check the
of Medical Cannabis Program Act or sale of assets by gaming licensee, box and enter the entire FEIN of the member who prepared Illinois
or pass-through withholding or PTE tax payments on your original or Schedule UB. Attach Schedule UB to the return.
amended return, and no overpayment will result. Complete Steps 2 P — Enter your North American Industry Classification System
through 5, Step 6, if applicable, and Step 7, Lines 47 through 49. (NAICS) Code. If you are unsure of your code, you can research the
Sign the return in Step 10 and leave the rest of the form blank. information at www.census.gov/naics/ or www.irs.gov.
D — You must check the box and attach Form IL-4562, Special Q — Enter your Illinois corporate file (charter) number provided to
Depreciation, if you are claiming special depreciation addition or you by the Secretary of State.
subtraction modifications on Form IL-1120-ST-X, even if the amounts
R — If you are filing Form IL-1120-ST-X on or before the extended
are not changing from your original return.
due date and wish to make the election to treat all income, other
E — You must check the box and attach Schedule M, Other than compensation, as business income for this tax year, check
Additions and Subtractions (for businesses), if you are claiming other this box. If you previously reported nonbusiness income on
addition or subtraction modifications on Form IL-1120-ST-X, even if Form IL-1120-ST, Step 6, Lines 36 and 44, you must reduce these
the amounts are not changing from your original return. amounts to zero on this Form IL-1120-ST-X. This election must
F — You must check the box and attach Schedule 80/20, be made by the extended due date of the original tax return. Once
Related-Party Expenses, if you are claiming related-party expenses made, the election is irrevocable. If you are filing Form IL-1120-ST-X
modifications on your Form IL-1120-ST-X, even if the amounts are after the extended due date of the original return and did not make
not changing from your original return. the election on your original return, you cannot check this box.
G — Check the box if you are claiming deductions or credits listed S — If you have completed federal Form 8886 or federal
on Illinois Schedule 1299-A, Tax Subtractions and Credits (for Schedule M-3, Part II, Line 10, to report a tax shelter and you did
partnerships and S corporations). You must check the box and not attach a copy to the original return, check the appropriate box
attach Illinois Schedule 1299-A and any other required support listed and attach a copy of the federal form or schedule to this return. If
on Schedule 1299-A to your tax return to support any deductions or you are filing this return because of changes associated with federal
credits you are claiming or passing to your shareholders. Form 8886 or federal Schedule M-3, Part II, Line 10, provide a
H — If you are attaching Subgroup Schedule to your Schedule UB, detailed explanation in the “Explain the changes on this return” area.
Combined Apportionment for Unitary Business Group check the box. T — Check the box if you must adjust loss or loss carryover due
See Subgroup Schedule Instructions and Schedule UB Instructions to discharge of indebtedness. For more information, see the
for more information. Form IL-1120-ST, Step 7, Line 48 instructions and Schedule NLD
I — Check the appropriate box for the reason you are filing instructions.
this return. If you are amending due to a federal change, you U — If your business activity is protected under Public Law 86-272,
must check the appropriate box for partial agreed or finalized and check this box and complete Steps 1 through 7 of your IL-1120-ST-X.
include the date of IRS finalization, which might not be the date the V — Check this box if you are paying Pass-through Entity (PTE) Tax
federal amended return was filed. Attach a dated copy of any federal and you annualized your income on Form IL-2220, Computation of
examining officer’s report. If you do not provide this date or the Penalties for Businesses. Attach Form IL-2220.
required attachments, you may be assessed penalties and interest.
IL-1120-ST-X Instructions (R-12/23) Page 3 of 6

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                                                                             If you need to make a correction to Line 20 or Line 24, 
   Explain the changes on this return                                   use the worksheet located in the Schedule B Instructions of the 
This area allows you to explain what specific changes you are           Form IL-1120-ST Instructions to figure the correct amounts. You 
making to your Illinois tax return. You should include all relevant     must attach a corrected Illinois Schedule B if there is a change 
information, including, but not limited to, changes made to             in the information reported on your most recently filed Illinois 
• specific addition and subtraction modifications,                      Schedule B.
• unitary membership or unitary status,                                 Line 35 — This is your base income or loss.
• the business income election,                                         Column A — Enter the amounts from your most recently filed or 
• credit or credit recapture amounts,                                   adjusted return. Do not check a box on Lines A or B to indicate 
• the Illinois net operating loss deduction, and                        how your income was reported on your most recently filed or 
• the federal or other state return that caused changes to the          adjusted return. The check boxes on Lines A and B are used when 
  Illinois return.                                                      reporting your amended base income or loss in column B.
You must provide an explanation for each line item you change.          Column B — Follow the instructions on the form and check the 
If your changes generate an overpayment which you elect to receive      box on Line A or B that applies to the amount in Column B. You must 
as a credit carryforward and you elect to apply that credit to a tax    check one of these boxes and follow the instructions for that line 
year other than the year described in the Line 70 instructions, you     when completing Column B.
must follow the instructions found under “May I apply my credit to a    Check the box on Line A if
different tax year?” If you fail to include the required information in • all of your base income or loss is derived inside Illinois; and
your explanation, your election will be considered invalid and we will  • you do not have any income or loss to report on Lines 36, 37, 
not apply your credit as you requested.                                   44, or 45.
                                                                        If you check the box on Line A, do not complete Step 6, 
General Information for Steps 2 through 9                                         All of your amended base income or loss is allocable 
                                                                        Column B.
Column A — Enter the amounts from your most recently filed or           to Illinois. Skip Step 6, Column B, enter the amount from Step 5, 
adjusted return for the year that you are amending. These may be        Column B, Line 35 on Step 7, Column B, Line 47, and complete the 
figures from your original Form IL-1120-ST, or a previously amended     remainder of the return.
or audited return.
                                                                        Check the box on Line B if any of the following apply:
Column B — Enter the correct amount for each line in Column B.          • your base income or loss is derived inside and outside Illinois; 
For each line item you change, you must provide an explanation of 
                                                                        • all of your base income or loss is derived outside Illinois; or
the change in the “Explain the changes on this return” area of your 
return.                                                                 • you have income or loss to report on Lines 36, 37, 44, or 45.
For instructions regarding completion of Steps 2 through 9, refer to    If you check the box on Line B, you must complete all lines 
the Form IL-1120-ST Instructions and schedules for the year being       of Step 6, Column B. Submitting Form IL-1120-ST-X with an 
amended.                                                                incomplete Step 6, Column B, including Lines 40, 41, and 42 may 
                                                                        result in a delay in processing your return, further correspondence, 
         If you are filing this form only to report an increase in your 
                                                                        and you may be required to submit further information to support 
Illinois net loss, you have no surcharges for Compassionate Use of 
                                                                        your filing. See the Specific Instructions for Step 6 for more 
Medical Cannabis Program Act or sale of assets by gaming licensee 
                                                                        information.
or pass-through withholding payments to report on behalf of your 
members on your original or amended return, and the change will not          Unitary filers - You must complete both Step 4 of the 
result in an overpayment, see the instructions for Step 7, Line 47.     Schedule UB and Step 6, Column B of the Form IL-1120-ST-X.

Step 2 and Step 3:  Figure your ordinary income                         Step 6:  Figure your income allocable to Illinois
                                                                        Complete Step 6 only if you originally completed this step, or you 
or loss and Figure your unmodified base                                 need to make a change that affects your base income or loss 
income or loss                                                          allocable to Illinois. Refer to Form IL-1120-ST, Step 6, Specific 
         If you are a member of a unitary group see “What if I am a     Instructions, for the year being amended.
member of a unitary group?“ and the instructions for Steps 2 and 3 in   You must check the box on Line B and complete Step 6 if any 
the Form IL-1120-ST instructions.                                       portion of Step 5, Column B, Line 35, base income or loss, is 
Lines 1 through 13 — Refer to your Form IL-1120-ST,                     derived outside Illinois, or you have any income or loss to report on 
Steps 2 and 3, Specific Instructions, for the year being amended.       Column B, Lines 36, 37, 44, or 45.  
         Do not apply your Illinois net loss deduction (NLD) amount in  If you do not complete all of Step 6, Column B, Lines 36 through 46, 
this step. NLDs are reported on Step 7, Line 50.                        we may issue a notice and demand proposing 100 percent of income 
                                                                        as being allocated to Illinois, or in the case of a loss return, a notice 
Step 4 and Step 5:  Figure your income or loss                          indicating none of your loss as being allocated to Illinois. 
and Figure your base income or loss                                     Lines 36 and 44 — If you elected to treat all of your income other 
         If you are a member of a unitary group see “What if I am a     than compensation as business income on your original tax return, 
member of a unitary group?“ and the instructions for Step 4 in the      you must follow that election by entering zero on Form IL-1120-ST-X, 
Form IL-1120-ST instructions.                                           Lines 36 and 44. If you are filing Form IL-1120-ST-X before 
Line 14 — If you are a member of a unitary group enter your             the extended due date and are making the election to treat all 
combined company income as shown on Schedule UB, Step 2,                nonbusiness income as business income, Column B, Lines 36 and 
Column E, Line 30. Otherwise, follow the instructions on the form.      44 should be reduced to zero.
Lines 15 through 21 and Lines 23 through 33 — List each 
item and the amount on the line provided. You must identify all 
subtractions and attach all of the required supporting documentation.

IL-1120-ST-X Instructions (R-12/23)                                                                                                  Page 4 of 6

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Step 7: Figure your net income Pass-through withholding payment amounts reported to you are
Line 47 — Follow the instructions on the form. If the amount included on Step 9, Line 63c.
in Column A reflects income and the corrected amount in You must also issue revised Schedule(s) K-1-P to your
Column B reflects a loss, you may be able to carry this loss to shareholders if any amounts reported to them on the original
other years as an Illinois NLD. See the instructions for Illinois Schedule(s) K-1-P you issued have changed. Mark the top of the
Schedule NLD for more information. revised Schedule(s) K-1-P you issue as “Revised.”
If you are filing this form only to report an increase in your Line 60 — Complete this line if you elect to pay PTE tax on your
Illinois net loss, you have no surcharges for Compassionate Use of calculated base income instead of pass-through withholding. Follow
Medical Cannabis Program Act or sale of assets by gaming licensee, or the instructions on Form IL-1120-ST, Line 60.
pass-through withholding or PTE tax payments on your original or Line 61 — If you complete Line 61, then Line 59 should be blank.
amended return, and the change will not result in an overpayment,
check the box in Step 1, Line C, complete Steps 2 through 5, Step 6, Step 9: Figure your refund or balance due
if applicable, and Step 7, Lines 47 through 50. Complete the “Explain If you are filing this form only to report an increase in your
the changes on this return” area stating what caused the increase in Illinois net loss, you have no surcharges for Compassionate Use of
the Illinois net loss and sign the return in Step 10. Leave the rest of Medical Cannabis Program Act or sale of assets by gaming licensee
the form blank. or pass-through withholding payments to report on behalf of your
members on your original or amended return, and an overpayment
Line 48 — If the amount on Line 47 is a loss, and you were
will not result, do not complete this step.
required to reduce the net operating loss reported on your U.S.
Form 1120S because you excluded any discharge of indebtedness Line 63a — Enter the sum of any overpayment from your prior
income from this tax year’s gross income, then you may be required year tax returns that you requested to be applied to this year’s tax
to reduce the net loss reported on Line 47. Use the Loss Reduction return. Take into account any correspondence we may have sent
Worksheet in the Form IL-1120-ST instructions to figure your loss you that changed the amount of your credit carryforward from the
reduction. Attach a copy of your federal Form 982, Reduction previous year.
of Tax Attributes Due to Discharge of Indebtedness, to your Line 63b — Enter the sum of the following, not including any
Form IL-1120-ST-X. For more information, see 86 Ill. Adm. Code penalty and interest previously paid:
Section 100.2310(c). • estimated payments or tax prepayments made during the tax
Line 49 — If you have a discharge of indebtedness adjustment year,
on Line 48, add Line 47 (a negative number) and Line 48 (a positive • extension payments,
number), and enter the result here. This amount cannot be greater • any tax payments you made with a previously filed
than zero. Form IL-1120-ST-X, and
If you do not have a discharge of indebtedness adjustment, • any other payments made prior to the date this amended return
enter zero on Line 48 and the amount from Line 47 on Line 49. is filed (e.g., responding to a bill).
Line 50 — Enter your Illinois NLD from the Illinois Schedule NLD, Line 63c — Enter the amount you wish to claim of Illinois
Step 1, Line 7 total box. Attach Illinois Schedule NLD to your pass-through withholding (including any eligible investment
Form IL-1120-ST-X. partnership withholding) payments reported to you by partnerships,
S corporations, or trusts on Schedule(s) K-1-P or K-1-T. If you
Step 8: Figure the taxes, surcharges, and received more than one Schedule K-1-P or K-1-T, add the amounts
pass-through withholding you owe you wish to claim from all the schedules and enter the total here.
Follow the instructions on the form. Be sure to attach any required Attach copies of the Schedules K-1-P and K-1-T you received
schedules or forms. from the pass-through entities to your Form IL-1120-ST-X. See
Line 53 — See Illinois Schedule 4255, Recapture of Investment “Definitions to help you complete your Form IL-1120-ST” in the
Credits, for more information. You must attach Illinois Schedule 4255 Form IL-1120-ST instructions for more information.
if you have an amount on this line. Partners in an investment partnership may not be eligible to
Line 55 — See Form IL-477, Replacement Tax Investment Credits, claim a Schedule K-1-P, Step 7, Line 55 amount reported to them by
for more information. You must attach Form IL-477 and any other the investment partnership. See Schedule K-1-P(2) for information
required support listed on Form IL-477 if you have an amount on this about when a partner may claim investment partnership withholding
line. credit.
Line 57 — Compassionate Use of Medical Cannabis Program Act Do not include on Line 63c any pass-through withholding
surcharge. Use the instructions and the Surcharge Worksheet in the payments you owe on behalf of your members. Pass-through
Form IL-1120-ST instructions to figure your surcharge. withholding payments you owe on behalf of your members are
Line 58 — Sale of assets by gaming licensee surcharge. Use the included on Step 8, Line 59.
instructions and the Surcharge Worksheet in the Form IL-1120-ST Line 63d — Enter the amount of any Illinois gambling and sports
instructions to figure your surcharge. wagering winnings withholding shown on Form W-2G. Attach
Line 59 — Complete all sections of Illinois Schedule B and enter Form W-2G.
the amount from Illinois Schedule B, Section A, Line 5 on this line. Line 65 — Enter previously paid penalty and interest. This
This is the amount of pass-through withholding payments you owe information can be obtained from your MyTax Illinois account. Sign
on behalf of your members. You must attach a corrected Illinois into mytax.illinois.gov to view or register your account.
Schedule B if there is a change in the information reported on Line 66 — Enter the total amount of any overpayment, credit, or
your most recently filed Illinois Schedule B. See “Definitions to refund (whether or not you received the overpayment) reported on
help you complete your Form IL-1120-ST” in the Form IL-1120-ST your previously filed Form IL-1120-ST, or Form IL-1120-ST-X. Do not
instructions for more information. include any interest that you received.
Do not include on Line 59 any pass-through withholding
payments reported to you on Schedule(s) K-1-P or K-1-T.

IL-1120-ST-X Instructions (R-12/23) Page 5 of 6

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Line 70 — Enter the amount of overpayment you elect to be                   Step 10:  Signature, date, and paid preparer’s 
credited forward. Check the box on this line if this is your final return   information
and any remaining carryforward is being transferred to another              You must sign and date your return. If you do not sign your return, 
entity. Attach a detailed statement to your return listing the FEIN of      it will not be considered filed and you may be subject to a nonfiler 
the entity receiving the credit carryforward, the date the credit was       penalty.
transferred, and the reason for the transfer. 
                                                                            If you pay someone to prepare your return, the income tax return 
See Form IL-1120-ST, Step 9, Line 68 instructions for more                  preparer must also sign and date the return, enter the preparer tax 
information.                                                                identification number (PTIN) issued to them by the Internal Revenue 
Your credit carryforward will not be applied if you do not file a           Service, and provide their firm’s name, FEIN, address, and phone 
processable return.                                                         number.
If your overpayment accrues interest and you elect to receive your          If you want to allow the paid preparer listed in this step to discuss 
• entire overpayment as a credit carryforward, any interest due will        this return with IDOR, check the box. This authorization will allow 
  be applied with your credit as an additional credit carryforward.         your paid preparer to answer any questions that arise during the 
  We will calculate the amount of interest due and notify you.              processing of your return, call us with questions about your return, 
  When you claim your credit carryforward in a future year you              and receive or respond to notices we send. The authorization will 
  must include this interest amount in the amount claimed.                  automatically end no later than one year after you file your amended 
• overpayment as both a credit carryforward and a refund, we will           return. You may revoke the authorization at any time by calling or 
  apply the credit as you request and include any interest due with         writing us.
  your refund.
         Your credit carryforward may be reduced by us due to 
corrections we make to your return, or to satisfy any unpaid tax, 
penalty, and interest due for this year or any other year. If we reduce 
your credit carryforward, it may result in a late-payment penalty in a 
subsequent year.
May I apply my credit to a different tax year? 
Yes. If you wish to apply your credit to a tax year other than the one 
described above, you must indicate the tax year to which you wish to 
have the credit apply in the “Explain the changes on this return”  area 
of this return.
If you do not follow these instructions, your election will be 
considered invalid and we will apply your credit as indicated 
under “To which tax year will my credit apply?” in the original return 
instructions.
If you submit a valid request, we will apply your credit as you requested 
and notify you. Once made, your election to change the tax year to which 
your credit will apply is irrevocable. 
         You may only apply your credit to tax years occurring after 
the year of the return creating the overpayment. If you request to apply 
more credit than our records show you have available, we will apply the 
maximum amount available and notify you of the difference.
Line 71 — Follow the instructions on the form. We will calculate any 
interest that may be due you and include it in your refund check. Any 
refund may be reduced to satisfy any outstanding liability.
We do not currently offer direct deposit as a method for receiving a refund 
from an amended return. Overpayments will be refunded by check.
Line 72 — Follow the instructions on the form. This is your amount 
of tax due that must be paid in full if $1 or more. We encourage you to 
let us figure your penalties and interest and send you a bill instead of 
determining these amounts yourself.   We will compute any penalty and 
interest due and notify you. For more information see “What are the 
penalties and interest?” and Publication 103. 
         We will apply all payments against tax first, penalty second, 
and interest third.
If you have a balance due on Line 72 be sure to enter the amount you 
are paying on the top of Page 1 of the Form IL-1120-ST-X. Complete 
a payment voucher, Form IL-1120-ST-X-V, make your check or 
money order payable to “Illinois Department of Revenue”  , and 
attach them to the front of the return or file and pay electronically.

IL-1120-ST-X Instructions (R-12/23)                                                                                                     Page 6 of 6

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