September 2026
September 15, 2026
Return Filing Deadlines
Extension Deadline Partn. & S-Corps.
Extended deadline for Partnerships and S-Corporations to file annual tax returns.
September 15, 2026
Estimated Payments Deadlines
3rd Quarter Estimated Tax Payment
Estimated tax payments for the 3rd quarter of 2025 are due for C-Corporations and Individuals.