09/08/2026
🚨 SEPTEMBER 15 TAX DEADLINE IS COMING
September 15 is an important tax deadline for many business owners and self-employed taxpayers.
Here’s what may be due:
📌 S-CORPORATIONS
If your 2025 S-Corp tax return was extended, Form 1120-S is generally due September 15.
📌 PARTNERSHIPS
Extended 2025 partnership returns (Form 1065) are generally due September 15.
📌 Q3 ESTIMATED TAXES
Self-employed individuals, business owners, partners, and S-Corp shareholders who make estimated tax payments may have their third 2026 payment due September 15.
📌 BUSINESS OWNERS
Don’t assume filing an extension means you have more time after September 15. For many extended partnership and S-Corp returns, this is the final filing deadline.
Not sure if this deadline applies to you?
McPhee Accounting can help you understand what needs to be filed and what may be due.
📅 September 15, 2026
Don’t wait until the last minute.