S Corporation Tax Deadlines in Montana
Federal and state filing dates, extensions, and estimate schedules for 2026.
Montana filing deadline
Calendar-year due date follows federal timing for pass-through entities.
Due: Mar 16, 2026
Extension: Sep 15, 2026
Form: State business income tax return
Estimated payments
No state estimated payment schedule listed.
Due: N/A
FAQ
Does Montana require S Corporation estimated payments?
Estimated payments are not typically required at the entity level, but confirm with Montana Department of Revenue.
Where can I file Montana S Corporation taxes?
Use Montana Department of Revenue resources at https://mtrevenue.gov for forms and filing instructions.