Tax Law and News

September 2025 tax and compliance deadlines

Written by Christopher J. Picciurro, CPA/PFS, MBA, ARA
Modified Aug 27, 2025
1 min read

What’s up in September? For many tax pros, you’ll get back to business after a busy summer with family and friends. For others, important extension filings are just around the corner and you’re getting ready for those. Along the way, check out these important tax and compliance deadlines for September 2025, and be sure to share this list with your clients.

In September, it is recommended that you:

Finalize extended returns: Complete S Corporation and partnership returns before the September 15 deadline
Confirm estimated tax payments: Notify clients about the 3rd estimated tax payment and confirm submission.
Conduct year-end tax planning: Identify tax-saving strategies for high-net-worth individuals and business clients.
Join a new professional group or mastermind: Find a group that focuses on tax strategy, business growth, or even something unrelated to tax.

Key Compliance Dates

Wednesday, September 10—Tips reporting for August.

Friday, September 12—Regular method excise taxes deposit for the last 16 days of August.

Monday, September 15:

3rd installment of 2025 estimated tax (individuals and corporations).
S Corporation (1120-S) and Partnership (1065) returns due (if extended).
Monthly payroll tax deposit for August (Form 941).

Thursday, September 25—Communications and air transportation taxes deposit for the last 16 days of August.

Monday, September 29— Regular method excise taxes deposit for the first 15 days of September.

Tuesday, September 30:

Wagering tax (Form 730) and Heavy Highway Vehicle Use Tax (Form 2290) for August due.
Final due date for special September deposit rules (excise tax).

Intuit® Accountant Resources

The September 2025 calendar with filing deadlines and reminders for you and your clients.
One Big Beautiful Bill summary and tax changes
Navigating the tax landscape
Intuit Tax Guide 2024
IRS annual inflation adjustments for tax years 2024 and 2025
Key Tax Facts for 2024 and Key Tax Facts for 2025

Chris Picciurro is a highly respected expert in U.S.-based tax planning and strategy for real estate investors. Based in Franklin, TN, where he resides with his family, Chris is an accomplished public speaker, recognized for delivering informative and engaging presentations at notable events hosted by organizations such as the National Association of Tax Professionals (NATP), Michigan Association of CPAs, and the Memphis Investment Group. He also previously participated as an Adjust Professor at Baker College and Davenport University. Chris served on the Intuit Tax Council from 2017-2020, and is a co-founder and executive officer of the Integrated CPA Group, founder of Teaching Tax Flow, and the Monthly Recurring Revenue Institute. More from Christopher J. Picciurro, CPA/PFS, MBA, ARA