Employees working in Montana need to complete a Montana Employee's Withholding Allowance and Exemption Certificate (Form MW-4) so their employers can withhold Montana income tax from their paychecks.
The Montana Department of Revenue will no longer accept the federal Form W-4. The federal Form W-4 should only be used for federal withholding purposes.
Your employee should complete Form MW-4 if they:
Your employee should consider completing a new Form MW-4 if their personal or financial situation changes.
They may be charged interest, penalties, or both when they file their individual income tax return if they do not have enough income tax withheld from their wages.
See Late Fees, Interest, and Penalties for more information on interest and penalties on underpaid estimated taxes.
You must file your employee's Form MW-4 with the Department of Revenue only if the employee is claiming one of the withholding exemptions on line 5 of the updated Form MW-4.
If an employee provides you with a Form MW-4 that meets one or both of the conditions above, you must submit this form to the department by the last day of the payroll period in which the form was received.
File online using the department's TransAction Portal (TAP).
For security reasons, employers must be logged into their TAP accounts to submit the Form MW-4.
Do not mail the Form MW-4 to the department.
You should keep a copy of all Forms MW-4 you receive from your employees with your records.