Rule 42.2.307 - ACCOUNTING METHODS(1) The taxpayer's method of accounting must be the method of accounting for federal income tax purposes. If the taxpayer's accounting method is changed for federal income tax purposes, the accounting method for Montana income tax purposes is automatically changed to reflect the same method.(2) Acceptable accounting methods include the cash basis, accrual method, a hybrid of the cash and accrual methods, or any other method permitted under section 446 of the IRC.Eff. 12/31/72; AMD and TRANS, from ARM 42.15.211, 2004 MAR p. 1965, Eff. 8/20/04; AMD, 2014 MAR p. 1527, Eff. 7/11/14.15-30-2620, 15-31-501, MCA; IMP, 15-30-2101, 15-30-2111, 15-31-113, 15-31-114, MCA;