1. (1) An original return is due on the prescribed filing date, as described in 15-30-2604, MCA, and ARM 42.15.319. The date prescribed for filing is the original return's due date, excluding extensions.
2. (2) An original return is the Montana Form 2.
3. (3) An amended return is not an original return but only a correction to an original return.
4. (4) The department will not accept an amended return if an original return has not been filed.
5. (5) Interest, late filing, and late payment penalties are assessed as required under 15-1-216, MCA, on the amount due reported on the original return.
6. (6) Interest, late filing, and late payment penalties are calculated from the due date in (1), and adjusted based on the corrected amount of tax due, which results from an amended return, adjustment from an audit, or correction to the original return.
7. (7) Taxes are due on the prescribed filing date. When an original return is filed after the prescribed date, but before the extended due date and payment is not made, the tax due is subject to interest and the late payment penalty.

8. (8) The department may not issue a credit or refund of an overpayment of taxes shown on a return if:

   1. (a) the return is filed more than one year after the expiration of a suspension of the federal statute of limitations for the collection of federal income tax;
   2. (b) the return is filed more than three years after the prescribed filing date;
   3. (c) for tax years beginning after December 31, 2016, the original return is filed more than three years after the date prescribed for filing and one year after an overpayment is made; or
   4. (d) the return is filed more than 40 months and 15 days after the last month of the tax year that a net operating loss occurred within the limitations provided in 15-30-2609(2)(b), MCA.
9. (9) When an original return is filed after the extended due date, and the department does not issue the requested refund within 45 days of receiving the return, interest as allowed under 15-30-2609, MCA, is payable from the date the return was filed. For example, an original return for tax year 20X1 requesting a refund is filed November 12, 20X2, and the department does not issue the refund until January 30, 20X3. Refund interest is payable from the date the return was filed (November 12, 20X2) until the date the refund was issued (January 30, 20X3).

10. (10) The department may not pay interest on a refund under 15-30-2609, MCA, if the refund is:

    1. (a) issued 45 days before the latter of:

       1. (i) the prescribed filing date in (1); or
       2. (ii) when the return was filed;
    2. (b) as a result of a federal net operating loss carryback;
    3. (c) in an amount less than $1;
    4. (d) not the result of an actual tax liability; or
    5. (e) from an amount by a taxpayer in which no items of Montana source income or loss were reported for the period.

11. (11) If the department sends a request for information to a taxpayer regarding a pending refund, the taxpayer must respond or request additional time within 30 days of the date of the request.

    1. (a) If the taxpayer responds to the request from the department, interest will accrue from the date prescribed under 15-30-2609, MCA.
    2. (b) If the taxpayer responds to the request after 30 days absent an agreement with the department for additional response time, interest will not accrue from the date of the request until the requested information is received by the department.
    3. (c) If the taxpayer fails to respond to the request, the department may deny the refund request and issue an adjustment letter which explains the denial, as provided in ARM 42.2.510.

Authorizing statute(s): 15-30-2620, MCA

Implementing statute(s): 15-1-216, 15-30-2512, 15-30-2602, 15-30-2609, MCA

History: NEW, 1988 MAR p. 2745, Eff. 12/23/88; AMD, 1992 MAR p. 2555, Eff. 11/26/92; AMD, 1996 MAR p. 2605, Eff. 10/4/96; AMD, 2002 MAR p. 1096, Eff. 4/12/02; AMD, 2005 MAR p. 1592, Eff. 12/17/04; AMD, 2006 MAR p. 85, Eff. 1/13/06; AMD, 2008 MAR p. 178, Eff. 2/1/08; AMD, 2010 MAR p. 1088, Eff. 4/30/10; AMD, 2010 MAR p. 3026, Eff. 12/24/10; AMD, 2013 MAR p. 178, Eff. 2/1/13; AMD, 2016 MAR p. 2073, Eff. 11/11/16; AMD, 2025 MAR, 42-1088, Eff. 1/25/25.