Indiana Code - Taxation - Title 6, Section 6-8.1-6-3

Date of filing

Sec. 3. (a) A document, including a form, a return, a payment, or
a writing of any type, which must be filed with the department by a
prescribed date, is considered filed:
(1) in cases where it is mailed through the United States mail,
on the date displayed on the post office cancellation mark
stamped on the document's wrapper;
(2) in cases where it is delivered to the department in any
manner other than through the United States mail, on the date
on which the department physically receives the document; or
(3) in cases where a payment is made by an electronic fund
transfer, on the date the taxpayer's bank account is charged.
(b) If a document is sent through the United States mail by
registered mail, certified mail, or certificate of mailing, then the date
of the registration, certification, or certificate, as evidenced by any
record authenticated by the United States Post Office, is considered
the postmark date.
(c) If a document is mailed to the department through the United
States mail and is physically received after the appropriate due date
without a legible correct postmark, the person who mailed the
document will be considered to have filed the document on or before
the due date if the person can show by reasonable evidence to the
department that the document was deposited in the United States
mail on or before the due date.
(d) If a document is mailed to, but not received by, the
department, the person who mailed the document will be considered
to have filed the document on or before the due date if the person can
show by reasonable evidence to the department that the document
was deposited in the United States mail on or before the due date and
if the person files with the department a duplicate document within
thirty (30) days after the date the department sends notice that the
document was not received.

As added by Acts 1980, P.L.61, SEC.1. Amended by P.L.92-1987,
SEC.9; P.L.63-1988, SEC.15.

Last modified: May 28, 2006