Overview
Massachusetts employers that withhold state income tax from employee wages must file Form M-941, Employer's Return of Income Taxes Withheld, with the Massachusetts Department of Revenue (DOR). The filing frequency is based on the employer's projected annual withholding liability.
The TaxBandits API supports automation of Form M-941 for Massachusetts withholding.
Forms supported
| Form | Type | Filing frequency | Due date |
|---|---|---|---|
| Form M-941 | Withholding | Annual, Quarterly, or Monthly | Depends on assigned filing frequency |
Key compliance notes
- M-941 filing frequency. Massachusetts assigns employers a filing frequency based on projected annual withholding liability.
- Annual filers. Employers with annual withholding of $100 or less file annually, with the return due January 31 of the following year.
- Quarterly filers. Employers with annual withholding of $101–$1,200 file quarterly. Returns are due on the last day of the month following each quarter.
- Monthly filers. Employers with annual withholding of $1,201–$25,000 file monthly. Returns are generally due by the 15th of the following month, with special due dates for March, June, September, and December.
- Zero filing. A return must be filed even when no tax is due. Zero-dollar returns must be e-filed through MassTaxConnect.
Filing due dates
| Filing Frequency | Reporting Period | Due Date |
|---|---|---|
| Annual | Calendar year | January 31 |
| Quarterly | Q1: Jan–Mar | April 30 |
| Quarterly | Q2: Apr–Jun | July 31 |
| Quarterly | Q3: Jul–Sep | October 31 |
| Quarterly | Q4: Oct–Dec | January 31 |
| Monthly | Monthly | 15th of following month, with exceptions |
For monthly M-941 filers, returns for March, June, September, and December are due on the last day of the following month.
API endpoints
The TaxBandits API provides Massachusetts-specific endpoints for Form M-941. The utility methods — List, Delete, Transmit, RequestPdfUrls, and Status — are shared across State Withholding and UI reporting.
Form M-941 (Massachusetts Withholding)
- Create — Creates a new Massachusetts M-941 withholding return.
- Update — Updates a previously created M-941 return before transmission.
- Get — Retrieves the details of an existing M-941 return.
Common endpoints: For the remaining methods — List, Delete, Transmit, RequestPdfUrls, and Status — refer to the common endpoints shared across State Withholding and UI reporting.
All endpoints require an OAuth 2.0 access token. Call the Auth method and pass the token as a Bearer token in the request header.
New hire reporting
Massachusetts employers must report newly hired and rehired employees to the Massachusetts Department of Revenue within 14 days of the employee's first day of work. The requirement also applies to qualifying independent contractors.
Employers with 25 or more employees must submit new-hire reports electronically through MassTaxConnect.
Testing & notifications
Before filing, you can simulate the entire verification flow in our Sandbox environment without submitting real data to the Massachusetts Department of Revenue.
As an alternative to polling the Status endpoint, you can configure a webhook for the Status Payroll Filings Status Change event type to receive automated status updates.