Except as provided in 15-30-2539, each remitter shall withhold from each royalty payment made to a royalty owner an amount equal to the highest marginal tax rate in effect under 15-30-2103 of the net amount payable to the royalty owner.
Mont. Code Ann. § 15-30-2538, under Estimated Tax and Withholding.
Mont. Code Ann. § 15-30-2538
Except as provided in 15-30-2539, each remitter shall withhold from each royalty payment made to a royalty owner an amount equal to the highest marginal tax rate in effect under 15-30-2103 of the net amount payable to the royalty owner.