86 Ill. Adm. Code 140.1101
Filing of Documents with the Department
Section 140
Section 140.1101 Filing of
Documents with the Department
a) Any report, claim, tax return, statement or other document
required or authorized to be filed with or any payment made to the Department
of Revenue, which document or payment is transmitted through the United States
mail, will be deemed to have been filed with and received by the Department on
the date shown by the post office cancellation mark stamped upon the envelope
or other appropriate wrapper containing it. If mailed but not received by the
Department, or if received, but the cancellation mark is illegible, erroneous
or omitted, the document or payment will be deemed to have been filed on the
date it was mailed if the sender establishes by competent evidence that the
document or payment was deposited in the United States mail on or before the
date due for filing. If the envelope or other wrapper bears a postmark made by
a private postage meter in addition to a legible postmark made by the United
States Postal Service, the postmark not made by the United States Postal
Service shall be disregarded. In the event of the Department's failure to
receive a document or payment required by law to be filed, such document or
payment will be deemed to have been received by the Department on time if the
sender files with the Department a duplicate within 30 days after written
notification is given to the sender by the Department of its failure to receive
such document or payment, provided proof is furnished that the original of the
document was deposited in the United States mail on or before the date due for
filing.
b) If any report, claim, tax return, statement, remittance or
other document is sent by United States registered mail, certified mail or
certificate of mailing, a record authenticated by the United States Post Office
of such registration, certification or certificate shall be considered
competent evidence that the report, claim, tax return, statement, remittance or
other document was mailed, and the date of registration, certification or
certificate shall be deemed to be the postmarked date made by the United States
Postal Service.
c) If the due date for any return or other report or payment
falls on Saturday, Sunday or a Holiday, such due date shall be considered to be
the next business day either for the purpose of submitting such return or other
report or payment by mail or for the purpose of submitting such return or other
report or payment in person.
d) Reports, claims, tax returns, statements, remittances or other
documents delivered by means other than the United States mail are considered
to be filed on the date they are received by the Department.