Section 35.02.01.430 - PENALTY FOR FAILURE TO FILE, FAILURE TO PAY, OR DELINQUENT FILINGSections 63-3033, 63-3046, Idaho Code
01.In General. Due date means the date prescribed for filing without regard to extensions.02.Insufficient Postage. The proper amount of prepaid postage is required on returns mailed to the Tax Commission. If a tax return is returned to the sender due to insufficient postage, it may result in the return becoming delinquent and subject to the delinquency penalty specified by Section 63-3046(c), Idaho Code.03.Month Defined. If the due date falls on the last day of a calendar month, each succeeding calendar month, or fraction of it, during which the failure to file continues constitutes a month. If the due date is not the last day of the calendar month, the period that ends with the same date of the next month constitutes a month. If the succeeding month has no corresponding date, the last day of the month is substituted. Any fraction of a month from the date ending the preceding monthly period to the date of payment constitutes a full month.Idaho Admin. Code r. 35.02.01.430