BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Lyra Ventures LLC//FilingDates public calendars//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
NAME:Illinois business filing dates\, 2027 (FilingDates)
X-WR-CALNAME:Illinois business filing dates\, 2027 (FilingDates)
DESCRIPTION:Illinois business filing dates\, 2027. Each event links the off
 icial source it was computed from. Obligations without a verified source a
 re not in this feed\; the web page lists them as unsupported. A reminder o
 nly: confirm with the source before filing.
X-WR-CALDESC:Illinois business filing dates\, 2027. Each event links the of
 ficial source it was computed from. Obligations without a verified source 
 are not in this feed\; the web page lists them as unsupported. A reminder 
 only: confirm with the source before filing.
REFRESH-INTERVAL;VALUE=DURATION:P1D
X-PUBLISHED-TTL:P1D
BEGIN:VEVENT
UID:il:IL-1040-ES:2026-01-01:3@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270115
DTEND;VALUE=DATE:20270116
SUMMARY:Illinois: Individual estimated tax (IL-1040-ES) for 2026 — 4th pa
 yment (Schedule C filer)
DESCRIPTION:Applies to: An individual (including a sole proprietor) expecti
 ng 2026 Illinois tax over $1\,000 after withholding and credits pays by Ap
 ril 15\, June 15 and September 15\, 2026 and January 15\, 2027. Fiscal-yea
 r filers adjust the dates and are not covered.\nDue rule: 1st payment: Apr
 il 15 of the year the calendar year begins\; 2nd payment: June 15 of the y
 ear the calendar year begins\; 3rd payment: September 15 of the year the c
 alendar year begins\; 4th payment: January 15 of the year after the calend
 ar year begins\nSource: https://tax.illinois.gov/content/dam/soi/en/web/ta
 x/forms/incometax/documents/currentyear/individual/il-1040-es.pdf (retriev
 ed 2026-09-23)\nA reminder only: confirm with the source before filing. Yo
 u file\; this calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/inc
 ometax/documents/currentyear/individual/il-1040-es.pdf
CATEGORIES:Illinois,estimated-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Individual estimated tax (IL-1040-ES) for 2026 — 4t
 h payment (Schedule C filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Individual estimated tax (IL-1040-ES) for 2026 — 4t
 h payment (Schedule C filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2026-01-01:0:annual@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270120
DTEND;VALUE=DATE:20270121
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (annual 
 filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the calendar y
 ear ends\nState legal holidays are not compiled: if this date is a state h
 oliday\, the deadline moves to the next business day.\nSource: https://tax
 .illinois.gov/research/publications/pubs/retailers-overview-of-sales-and-u
 se-tax/requirements-for-retailers-who-file-form-st-1.html (retrieved 2026-
 09-23)\nA reminder only: confirm with the source before filing. You file\;
  this calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (ann
 ual filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (ann
 ual filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2026-10-01:0:quarterly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270120
DTEND;VALUE=DATE:20270121
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (quarter
 ly filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the quarter en
 ds\nState legal holidays are not compiled: if this date is a state holiday
 \, the deadline moves to the next business day.\nSource: https://tax.illin
 ois.gov/research/publications/pubs/retailers-overview-of-sales-and-use-tax
 /requirements-for-retailers-who-file-form-st-1.html (retrieved 2026-09-23)
 \nA reminder only: confirm with the source before filing. You file\; this 
 calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (qua
 rterly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (qua
 rterly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2026-12-01:0:monthly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270120
DTEND;VALUE=DATE:20270121
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (monthly
  filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the month ends
 \nState legal holidays are not compiled: if this date is a state holiday\,
  the deadline moves to the next business day.\nSource: https://tax.illinoi
 s.gov/research/publications/pubs/retailers-overview-of-sales-and-use-tax/r
 equirements-for-retailers-who-file-form-st-1.html (retrieved 2026-09-23)\n
 A reminder only: confirm with the source before filing. You file\; this ca
 lendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-UI-3-40:2026-10-01:0@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270131
DTEND;VALUE=DATE:20270201
SUMMARY:Illinois: Quarterly wage report (UI-3/40) and contributions — UI-
 3/40
DESCRIPTION:Applies to: An employer the preparer lists as a quarterly Illin
 ois unemployment-insurance filer\, and does not attest is a reimbursing em
 ployer\, files wage reports (Form UI-3/40) and pays contributions by April
  30\, July 31\, October 31 and January 31. Governmental organizations and 
 some nonprofits that reimburse IDES for benefits instead of paying contrib
 utions are not dated by this line. The source states no weekend rule\, so 
 the stated date is shown.\nDue rule: UI-3/40: last day of the month after 
 the quarter ends\nFalls on a Sunday\; the source states no weekend rule.\n
 Source: https://ides.illinois.gov/employer-resources/taxes-reporting/quart
 erly-filing-requirements.html (retrieved 2026-09-23)\nA reminder only: con
 firm with the source before filing. You file\; this calendar reminds.
URL;VALUE=URI:https://ides.illinois.gov/employer-resources/taxes-reporting/
 quarterly-filing-requirements.html
CATEGORIES:Illinois,unemployment-insurance
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Quarterly wage report (UI-3/40) and contributions —
  UI-3/40
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Quarterly wage report (UI-3/40) and contributions —
  UI-3/40
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-941:2026-10-01:0@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270201
DTEND;VALUE=DATE:20270202
SUMMARY:Illinois: Form IL-941 quarterly withholding return (2026) — Form 
 IL-941
DESCRIPTION:Applies to: An employer the preparer attests pays amounts subje
 ct to Illinois withholding (not only household employees\, whose withholdi
 ng can go on Form IL-1040): for 2026\, Form IL-941 is due April 30\, July 
 31\, November 2 (October 31 falls on a Saturday) and February 1\, 2027. Il
 linois has no annual reconciliation return.\nDue rule: Form IL-941: last d
 ay of the month after the quarter ends\nStated date 2027-01-31\, moved to 
 the next business day.\nState legal holidays are not compiled: if this dat
 e is a state holiday\, the deadline moves to the next business day.\nSourc
 e: https://tax.illinois.gov/forms/withholding/currentyear/il-941-instr.htm
 l (retrieved 2026-09-23)\nA reminder only: confirm with the source before 
 filing. You file\; this calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/forms/withholding/currentyear/il-941
 -instr.html
CATEGORIES:Illinois,withholding
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form IL-941 quarterly withholding return (2026) — F
 orm IL-941
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form IL-941 quarterly withholding return (2026) — F
 orm IL-941
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-01-01:0:monthly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270222
DTEND;VALUE=DATE:20270223
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (monthly
  filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the month ends
 \nStated date 2027-02-20\, moved to the next business day.\nState legal ho
 lidays are not compiled: if this date is a state holiday\, the deadline mo
 ves to the next business day.\nSource: https://tax.illinois.gov/research/p
 ublications/pubs/retailers-overview-of-sales-and-use-tax/requirements-for-
 retailers-who-file-form-st-1.html (retrieved 2026-09-23)\nA reminder only:
  confirm with the source before filing. You file\; this calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-02-01:0:monthly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270322
DTEND;VALUE=DATE:20270323
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (monthly
  filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the month ends
 \nStated date 2027-03-20\, moved to the next business day.\nState legal ho
 lidays are not compiled: if this date is a state holiday\, the deadline mo
 ves to the next business day.\nSource: https://tax.illinois.gov/research/p
 ublications/pubs/retailers-overview-of-sales-and-use-tax/requirements-for-
 retailers-who-file-form-st-1.html (retrieved 2026-09-23)\nA reminder only:
  confirm with the source before filing. You file\; this calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-1065:2026-01-01:0@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270415
DTEND;VALUE=DATE:20270416
SUMMARY:Illinois: Form IL-1065 partnership replacement tax return — IL-10
 65 (calendar-year partnership)
DESCRIPTION:Applies to: A partnership's Form IL-1065 is due the 15th day of
  the 4th month after its taxable year closes\, with an automatic six-month
  filing extension.\nDue rule: IL-1065: 15th day of the 4th month after the
  tax year ends\nExtended due date: 2027-10-15\nSource: https://tax.illinoi
 s.gov/questionsandanswers/answer.74.html (retrieved 2026-09-23)\nA reminde
 r only: confirm with the source before filing. You file\; this calendar re
 minds.
URL;VALUE=URI:https://tax.illinois.gov/questionsandanswers/answer.74.html
CATEGORIES:Illinois,income-franchise-return
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form IL-1065 partnership replacement tax return — I
 L-1065 (calendar-year partnership)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form IL-1065 partnership replacement tax return — I
 L-1065 (calendar-year partnership)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-1120:2026-01-01:0@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270415
DTEND;VALUE=DATE:20270416
SUMMARY:Illinois: Form IL-1120 corporation income and replacement tax retur
 n — IL-1120 (calendar-year C corporation)
DESCRIPTION:Applies to: A corporation with net income or loss under the Ill
 inois Income Tax Act\, or qualified to do business in Illinois (the prepar
 er attests Illinois-source income or Illinois registration)\, that is not 
 a cooperative (a cooperative is due the 15th day of the 9th month\, not da
 ted here) whose tax year ends on a date other than June 30 files by the 15
 th day of the 4th month after the year closes\, with an automatic seven-mo
 nth filing extension (tax years ending on or after December 31\, 2021). Th
 e source states no weekend rule\, so the stated date is shown.\nDue rule: 
 IL-1120: 15th day of the 4th month after the tax year ends\nExtended due d
 ate: 2027-11-15\nSource: https://tax.illinois.gov/questionsandanswers/answ
 er.69.html (retrieved 2026-09-23)\nA reminder only: confirm with the sourc
 e before filing. You file\; this calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/questionsandanswers/answer.69.html
CATEGORIES:Illinois,income-franchise-return
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form IL-1120 corporation income and replacement tax r
 eturn — IL-1120 (calendar-year C corporation)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form IL-1120 corporation income and replacement tax r
 eturn — IL-1120 (calendar-year C corporation)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-business-estimates:2027-01-01:0@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270415
DTEND;VALUE=DATE:20270416
SUMMARY:Illinois: Business estimated tax (IL-1120-ES / IL-516-B) — 1st es
 timate (calendar-year S corporation\, C corporation or partnership)
DESCRIPTION:Applies to: A corporation expecting more than $400 of income an
 d replacement tax (or an electing partnership or S corporation expecting m
 ore than $500 of replacement and PTE tax) pays by the 15th day of the 4th\
 , 6th\, 9th and 12th months of the tax year. A weekend or holiday date mov
 es to the next business day.\nDue rule: 1st estimate: 15th day of the 4th 
 month of the tax year\; 2nd estimate: 15th day of the 6th month of the tax
  year\; 3rd estimate: 15th day of the 9th month of the tax year\; 4th esti
 mate: 15th day of the 12th month of the tax year\nState legal holidays are
  not compiled: if this date is a state holiday\, the deadline moves to the
  next business day.\nSource: https://tax.illinois.gov/businesses/business-
 income-tax-estimated-payments.html (retrieved 2026-09-23)\nA reminder only
 : confirm with the source before filing. You file\; this calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/businesses/business-income-tax-estim
 ated-payments.html
CATEGORIES:Illinois,estimated-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Business estimated tax (IL-1120-ES / IL-516-B) — 1s
 t estimate (calendar-year S corporation\, C corporation or partnership)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Business estimated tax (IL-1120-ES / IL-516-B) — 1s
 t estimate (calendar-year S corporation\, C corporation or partnership)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-01-01:0:quarterly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270420
DTEND;VALUE=DATE:20270421
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (quarter
 ly filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the quarter en
 ds\nState legal holidays are not compiled: if this date is a state holiday
 \, the deadline moves to the next business day.\nSource: https://tax.illin
 ois.gov/research/publications/pubs/retailers-overview-of-sales-and-use-tax
 /requirements-for-retailers-who-file-form-st-1.html (retrieved 2026-09-23)
 \nA reminder only: confirm with the source before filing. You file\; this 
 calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (qua
 rterly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (qua
 rterly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-03-01:0:monthly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270420
DTEND;VALUE=DATE:20270421
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (monthly
  filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the month ends
 \nState legal holidays are not compiled: if this date is a state holiday\,
  the deadline moves to the next business day.\nSource: https://tax.illinoi
 s.gov/research/publications/pubs/retailers-overview-of-sales-and-use-tax/r
 equirements-for-retailers-who-file-form-st-1.html (retrieved 2026-09-23)\n
 A reminder only: confirm with the source before filing. You file\; this ca
 lendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-UI-3-40:2027-01-01:0@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270430
DTEND;VALUE=DATE:20270501
SUMMARY:Illinois: Quarterly wage report (UI-3/40) and contributions — UI-
 3/40
DESCRIPTION:Applies to: An employer the preparer lists as a quarterly Illin
 ois unemployment-insurance filer\, and does not attest is a reimbursing em
 ployer\, files wage reports (Form UI-3/40) and pays contributions by April
  30\, July 31\, October 31 and January 31. Governmental organizations and 
 some nonprofits that reimburse IDES for benefits instead of paying contrib
 utions are not dated by this line. The source states no weekend rule\, so 
 the stated date is shown.\nDue rule: UI-3/40: last day of the month after 
 the quarter ends\nSource: https://ides.illinois.gov/employer-resources/tax
 es-reporting/quarterly-filing-requirements.html (retrieved 2026-09-23)\nA 
 reminder only: confirm with the source before filing. You file\; this cale
 ndar reminds.
URL;VALUE=URI:https://ides.illinois.gov/employer-resources/taxes-reporting/
 quarterly-filing-requirements.html
CATEGORIES:Illinois,unemployment-insurance
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Quarterly wage report (UI-3/40) and contributions —
  UI-3/40
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Quarterly wage report (UI-3/40) and contributions —
  UI-3/40
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-04-01:0:monthly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270520
DTEND;VALUE=DATE:20270521
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (monthly
  filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the month ends
 \nState legal holidays are not compiled: if this date is a state holiday\,
  the deadline moves to the next business day.\nSource: https://tax.illinoi
 s.gov/research/publications/pubs/retailers-overview-of-sales-and-use-tax/r
 equirements-for-retailers-who-file-form-st-1.html (retrieved 2026-09-23)\n
 A reminder only: confirm with the source before filing. You file\; this ca
 lendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-business-estimates:2027-01-01:1@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270615
DTEND;VALUE=DATE:20270616
SUMMARY:Illinois: Business estimated tax (IL-1120-ES / IL-516-B) — 2nd es
 timate (calendar-year S corporation\, C corporation or partnership)
DESCRIPTION:Applies to: A corporation expecting more than $400 of income an
 d replacement tax (or an electing partnership or S corporation expecting m
 ore than $500 of replacement and PTE tax) pays by the 15th day of the 4th\
 , 6th\, 9th and 12th months of the tax year. A weekend or holiday date mov
 es to the next business day.\nDue rule: 1st estimate: 15th day of the 4th 
 month of the tax year\; 2nd estimate: 15th day of the 6th month of the tax
  year\; 3rd estimate: 15th day of the 9th month of the tax year\; 4th esti
 mate: 15th day of the 12th month of the tax year\nState legal holidays are
  not compiled: if this date is a state holiday\, the deadline moves to the
  next business day.\nSource: https://tax.illinois.gov/businesses/business-
 income-tax-estimated-payments.html (retrieved 2026-09-23)\nA reminder only
 : confirm with the source before filing. You file\; this calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/businesses/business-income-tax-estim
 ated-payments.html
CATEGORIES:Illinois,estimated-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Business estimated tax (IL-1120-ES / IL-516-B) — 2n
 d estimate (calendar-year S corporation\, C corporation or partnership)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Business estimated tax (IL-1120-ES / IL-516-B) — 2n
 d estimate (calendar-year S corporation\, C corporation or partnership)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-05-01:0:monthly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270621
DTEND;VALUE=DATE:20270622
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (monthly
  filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the month ends
 \nStated date 2027-06-20\, moved to the next business day.\nState legal ho
 lidays are not compiled: if this date is a state holiday\, the deadline mo
 ves to the next business day.\nSource: https://tax.illinois.gov/research/p
 ublications/pubs/retailers-overview-of-sales-and-use-tax/requirements-for-
 retailers-who-file-form-st-1.html (retrieved 2026-09-23)\nA reminder only:
  confirm with the source before filing. You file\; this calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-04-01:0:quarterly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270720
DTEND;VALUE=DATE:20270721
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (quarter
 ly filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the quarter en
 ds\nState legal holidays are not compiled: if this date is a state holiday
 \, the deadline moves to the next business day.\nSource: https://tax.illin
 ois.gov/research/publications/pubs/retailers-overview-of-sales-and-use-tax
 /requirements-for-retailers-who-file-form-st-1.html (retrieved 2026-09-23)
 \nA reminder only: confirm with the source before filing. You file\; this 
 calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (qua
 rterly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (qua
 rterly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-06-01:0:monthly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270720
DTEND;VALUE=DATE:20270721
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (monthly
  filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the month ends
 \nState legal holidays are not compiled: if this date is a state holiday\,
  the deadline moves to the next business day.\nSource: https://tax.illinoi
 s.gov/research/publications/pubs/retailers-overview-of-sales-and-use-tax/r
 equirements-for-retailers-who-file-form-st-1.html (retrieved 2026-09-23)\n
 A reminder only: confirm with the source before filing. You file\; this ca
 lendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-UI-3-40:2027-04-01:0@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270731
DTEND;VALUE=DATE:20270801
SUMMARY:Illinois: Quarterly wage report (UI-3/40) and contributions — UI-
 3/40
DESCRIPTION:Applies to: An employer the preparer lists as a quarterly Illin
 ois unemployment-insurance filer\, and does not attest is a reimbursing em
 ployer\, files wage reports (Form UI-3/40) and pays contributions by April
  30\, July 31\, October 31 and January 31. Governmental organizations and 
 some nonprofits that reimburse IDES for benefits instead of paying contrib
 utions are not dated by this line. The source states no weekend rule\, so 
 the stated date is shown.\nDue rule: UI-3/40: last day of the month after 
 the quarter ends\nFalls on a Saturday\; the source states no weekend rule.
 \nSource: https://ides.illinois.gov/employer-resources/taxes-reporting/qua
 rterly-filing-requirements.html (retrieved 2026-09-23)\nA reminder only: c
 onfirm with the source before filing. You file\; this calendar reminds.
URL;VALUE=URI:https://ides.illinois.gov/employer-resources/taxes-reporting/
 quarterly-filing-requirements.html
CATEGORIES:Illinois,unemployment-insurance
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Quarterly wage report (UI-3/40) and contributions —
  UI-3/40
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Quarterly wage report (UI-3/40) and contributions —
  UI-3/40
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-07-01:0:monthly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270820
DTEND;VALUE=DATE:20270821
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (monthly
  filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the month ends
 \nState legal holidays are not compiled: if this date is a state holiday\,
  the deadline moves to the next business day.\nSource: https://tax.illinoi
 s.gov/research/publications/pubs/retailers-overview-of-sales-and-use-tax/r
 equirements-for-retailers-who-file-form-st-1.html (retrieved 2026-09-23)\n
 A reminder only: confirm with the source before filing. You file\; this ca
 lendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-business-estimates:2027-01-01:2@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270915
DTEND;VALUE=DATE:20270916
SUMMARY:Illinois: Business estimated tax (IL-1120-ES / IL-516-B) — 3rd es
 timate (calendar-year S corporation\, C corporation or partnership)
DESCRIPTION:Applies to: A corporation expecting more than $400 of income an
 d replacement tax (or an electing partnership or S corporation expecting m
 ore than $500 of replacement and PTE tax) pays by the 15th day of the 4th\
 , 6th\, 9th and 12th months of the tax year. A weekend or holiday date mov
 es to the next business day.\nDue rule: 1st estimate: 15th day of the 4th 
 month of the tax year\; 2nd estimate: 15th day of the 6th month of the tax
  year\; 3rd estimate: 15th day of the 9th month of the tax year\; 4th esti
 mate: 15th day of the 12th month of the tax year\nState legal holidays are
  not compiled: if this date is a state holiday\, the deadline moves to the
  next business day.\nSource: https://tax.illinois.gov/businesses/business-
 income-tax-estimated-payments.html (retrieved 2026-09-23)\nA reminder only
 : confirm with the source before filing. You file\; this calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/businesses/business-income-tax-estim
 ated-payments.html
CATEGORIES:Illinois,estimated-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Business estimated tax (IL-1120-ES / IL-516-B) — 3r
 d estimate (calendar-year S corporation\, C corporation or partnership)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Business estimated tax (IL-1120-ES / IL-516-B) — 3r
 d estimate (calendar-year S corporation\, C corporation or partnership)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-08-01:0:monthly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20270920
DTEND;VALUE=DATE:20270921
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (monthly
  filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the month ends
 \nState legal holidays are not compiled: if this date is a state holiday\,
  the deadline moves to the next business day.\nSource: https://tax.illinoi
 s.gov/research/publications/pubs/retailers-overview-of-sales-and-use-tax/r
 equirements-for-retailers-who-file-form-st-1.html (retrieved 2026-09-23)\n
 A reminder only: confirm with the source before filing. You file\; this ca
 lendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-07-01:0:quarterly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20271020
DTEND;VALUE=DATE:20271021
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (quarter
 ly filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the quarter en
 ds\nState legal holidays are not compiled: if this date is a state holiday
 \, the deadline moves to the next business day.\nSource: https://tax.illin
 ois.gov/research/publications/pubs/retailers-overview-of-sales-and-use-tax
 /requirements-for-retailers-who-file-form-st-1.html (retrieved 2026-09-23)
 \nA reminder only: confirm with the source before filing. You file\; this 
 calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (qua
 rterly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (qua
 rterly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-09-01:0:monthly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20271020
DTEND;VALUE=DATE:20271021
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (monthly
  filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the month ends
 \nState legal holidays are not compiled: if this date is a state holiday\,
  the deadline moves to the next business day.\nSource: https://tax.illinoi
 s.gov/research/publications/pubs/retailers-overview-of-sales-and-use-tax/r
 equirements-for-retailers-who-file-form-st-1.html (retrieved 2026-09-23)\n
 A reminder only: confirm with the source before filing. You file\; this ca
 lendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-UI-3-40:2027-07-01:0@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20271031
DTEND;VALUE=DATE:20271101
SUMMARY:Illinois: Quarterly wage report (UI-3/40) and contributions — UI-
 3/40
DESCRIPTION:Applies to: An employer the preparer lists as a quarterly Illin
 ois unemployment-insurance filer\, and does not attest is a reimbursing em
 ployer\, files wage reports (Form UI-3/40) and pays contributions by April
  30\, July 31\, October 31 and January 31. Governmental organizations and 
 some nonprofits that reimburse IDES for benefits instead of paying contrib
 utions are not dated by this line. The source states no weekend rule\, so 
 the stated date is shown.\nDue rule: UI-3/40: last day of the month after 
 the quarter ends\nFalls on a Sunday\; the source states no weekend rule.\n
 Source: https://ides.illinois.gov/employer-resources/taxes-reporting/quart
 erly-filing-requirements.html (retrieved 2026-09-23)\nA reminder only: con
 firm with the source before filing. You file\; this calendar reminds.
URL;VALUE=URI:https://ides.illinois.gov/employer-resources/taxes-reporting/
 quarterly-filing-requirements.html
CATEGORIES:Illinois,unemployment-insurance
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Quarterly wage report (UI-3/40) and contributions —
  UI-3/40
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Quarterly wage report (UI-3/40) and contributions —
  UI-3/40
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-10-01:0:monthly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20271122
DTEND;VALUE=DATE:20271123
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (monthly
  filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the month ends
 \nStated date 2027-11-20\, moved to the next business day.\nState legal ho
 lidays are not compiled: if this date is a state holiday\, the deadline mo
 ves to the next business day.\nSource: https://tax.illinois.gov/research/p
 ublications/pubs/retailers-overview-of-sales-and-use-tax/requirements-for-
 retailers-who-file-form-st-1.html (retrieved 2026-09-23)\nA reminder only:
  confirm with the source before filing. You file\; this calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-business-estimates:2027-01-01:3@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20271215
DTEND;VALUE=DATE:20271216
SUMMARY:Illinois: Business estimated tax (IL-1120-ES / IL-516-B) — 4th es
 timate (calendar-year S corporation\, C corporation or partnership)
DESCRIPTION:Applies to: A corporation expecting more than $400 of income an
 d replacement tax (or an electing partnership or S corporation expecting m
 ore than $500 of replacement and PTE tax) pays by the 15th day of the 4th\
 , 6th\, 9th and 12th months of the tax year. A weekend or holiday date mov
 es to the next business day.\nDue rule: 1st estimate: 15th day of the 4th 
 month of the tax year\; 2nd estimate: 15th day of the 6th month of the tax
  year\; 3rd estimate: 15th day of the 9th month of the tax year\; 4th esti
 mate: 15th day of the 12th month of the tax year\nState legal holidays are
  not compiled: if this date is a state holiday\, the deadline moves to the
  next business day.\nSource: https://tax.illinois.gov/businesses/business-
 income-tax-estimated-payments.html (retrieved 2026-09-23)\nA reminder only
 : confirm with the source before filing. You file\; this calendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/businesses/business-income-tax-estim
 ated-payments.html
CATEGORIES:Illinois,estimated-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Business estimated tax (IL-1120-ES / IL-516-B) — 4t
 h estimate (calendar-year S corporation\, C corporation or partnership)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Business estimated tax (IL-1120-ES / IL-516-B) — 4t
 h estimate (calendar-year S corporation\, C corporation or partnership)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:il:IL-ST-1:2027-11-01:0:monthly@filingdates.com
DTSTAMP:20260923T000000Z
DTSTART;VALUE=DATE:20271220
DTEND;VALUE=DATE:20271221
SUMMARY:Illinois: Form ST-1 sales and use tax return — Form ST-1 (monthly
  filer)
DESCRIPTION:Applies to: Form ST-1 and payment are due the 20th of the month
  after the reporting period (monthly\, quarterly\, or January 20 for annua
 l filers). Saturdays\, Sundays and Illinois holidays move to the next busi
 ness day.\nDue rule: Form ST-1: 20th day of the month after the month ends
 \nState legal holidays are not compiled: if this date is a state holiday\,
  the deadline moves to the next business day.\nSource: https://tax.illinoi
 s.gov/research/publications/pubs/retailers-overview-of-sales-and-use-tax/r
 equirements-for-retailers-who-file-form-st-1.html (retrieved 2026-09-23)\n
 A reminder only: confirm with the source before filing. You file\; this ca
 lendar reminds.
URL;VALUE=URI:https://tax.illinois.gov/research/publications/pubs/retailers
 -overview-of-sales-and-use-tax/requirements-for-retailers-who-file-form-st
 -1.html
CATEGORIES:Illinois,sales-tax
SEQUENCE:0
TRANSP:TRANSPARENT
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-P6DT15H
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Illinois: Form ST-1 sales and use tax return — Form ST-1 (mon
 thly filer)
TRIGGER:-PT15H
END:VALARM
END:VEVENT
END:VCALENDAR