Table of Contents

1099 E-Filing: Montana

Nina Tchistiakova Updated by Nina Tchistiakova

Due date

January 31

E-filing threshold

Specifications do not specify a filing threshold.

Filing options

Electronic filing

Forms to file

State requires W-2G and all 1099's.

Transmittal form

File Form MW-3 if state taxes were withheld.Payroll System doesn't support electronic filing of Form MW-3. See below for key and send.

Required file name

Any name with “.txt” at the end

E-filing website


E-Services Unit



Submitting files

Registering for a Montana TAP File Upload account allows employers, third party representatives, and payroll service providers the ability to file employer withholding forms W-2, 1099, and the Montana annual wage withholding tax reconciliation MW-3 form electronically.

File Upload

Sign into TAP.

Select Register to upload W-2, 1099 or withholding files and follow the steps provided.

Return to your TAP homepage and select the File processing account.

Select Submit new file and follow the steps provided

Single/Manual Entry of MW-3

1. Sign into TAP.

2. Select your Withholding account.

3. Select the File return link for the appropriate tax year and complete the form.

Note: Payments made throughout the year are already populated on the MW-3.

4. Verify that the withholding and payment totals are correct on lines 4 and 5. If the totals are not correct, you can adjust the amounts reported in Column C and Column D. You can also add/delete lines if necessary.

5. After completing all required fields and verifying the information is correct, select Submit.

For assistance submitting electronic W2s and 1099s, please contact e-services at:

Corrections to an original W-2, 1099 or MW-3 must be submitted on a paper form.

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