Oklahoma Administrative Code
Title 710 - Oklahoma Tax Commission
Chapter 65 - Sales and Use Tax
Subchapter 3 - Reports and Returns; Payments and Penalties; Records
Part 1 - GENERAL PROVISIONS
Section 710:65-3-2 - Timely mailing treated as timely filing and paying

(a) Any report, claim, tax return, statement or other document required or authorized to be filed with or any payment made to the Commission, which document or payment is transmitted through the United States mail, will be deemed to have been filed with and received by the Commission 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 Commission, or if received but the cancellation mark is illegible, erroneous or omitted, or envelope unavailable, 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 Commission's failure to receive a document or payment, the document or payment will be deemed to have been received by the Commission on time if the sender files with the Commission a duplicate within thirty (30) days after written notification is given to the sender by the Commission 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, certificate or certificates 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 date of the postmark made by the United States Postal Service. [See:710:1-3-30 through 710:1-3-32; 68 O.S. § 1365 ]