A valid extension of time in which to file a federal income tax return automatically extends the due date of the Oklahoma income tax return unless an Oklahoma liability is owed. A copy of the federal extension must be attached to the Oklahoma return. If the due date for filing the federal return is not extended or if an Oklahoma liability is owed, an extension of time to file the Oklahoma return may be granted only by filing OTC Form 504. Ninety percent (90%) of the tax liability must be paid by the original due date of the return to obtain a valid extension of time to file and avoid penalty charges for late payment. Interest will be charged from the original due date of the return.

Amended at 34 Ok Reg 2065, eff 9-11-17

Amended at 41 Ok Reg, Number 22, effective 8-11-24