Mont. Code Ann. § 15-30-2506

Every employer shall, prior to January 31 in each year, furnish to each employee a written statement showing the total wages paid by the employer to the employee during the preceding calendar year and showing the amount of the federal income tax deducted and withheld from the wages and the amount of the tax deducted and withheld under the provisions of 15-30-2501 through 15-30-2509. The statement must contain additional information and must be in the form that the department prescribes, and a duplicate of the statement must be filed by the employee with the employee's state income tax return.