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Essential October 2025 Tax Deadlines for Businesses

As October brings the refreshing chill of fall, it also reminds businesses of crucial tax deadlines that are fast approaching. Whether your business involves corporate filings, payroll deposits, or retirement plan contributions, staying updated with these dates is critical. Missing these can lead to unnecessary penalties and complications.

October 15 - Corporation Tax Filings

Businesses operating on a calendar year basis need to file their 2024 corporate income tax returns (Form 1120) by this date, assuming an automatic six-month extension was previously filed by April 15. Ensure all taxes, interests, and penalties are settled to maintain compliance.

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October 15 - Payroll Tax Deposits

Employers who follow the monthly deposit rule must deposit their Social Security, Medicare, and withheld income taxes by October 15 for the preceding month. This also applies to any nonpayroll withholdings for September 2025.

October 15 - Retirement Accounts

For the self-employed who obtained an extension for their 2023 tax filings, October 15 is the deadline to establish a Keogh Retirement Account and contribute for the 2024 tax year. Contributions for SEP IRAs must also be finalized by this date if your tax return is on extension.

October 31 - Various Employer Contributions

Employers need to file Form 941 for Q3 2025. Compliance with the accuracy of deposit rules is crucial; deposits should be complete unless the total liability is under $2,500, meaning full payment can accompany a timely-filed return. If taxes were deposited on time, November 10 is the extended filing deadline.

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October 31 - Adjustments for Small Employers

If your tax liability exceeds $2,500 for 2025 but was under $2,500 for Q3, ensure all taxes due are lodged.

October 31 - Federal Unemployment Tax


Deposits are required for taxes through September if the amount owed surpasses $500.

Flexibility in Deadlines:

Should a due date fall on a Saturday, Sunday, or legal holiday, it automatically extends to the next business day.

Reliefs for Disaster Areas:

In natural disaster situations where an area is officially declared a disaster zone, filing deadlines might be adjusted. For updates, visit FEMA and the IRS for accurate information.

At Thompson-Smith CPA, LLC., we understand the diverse challenges businesses face during tax season. With Georgia Smith’s two decades of experience, we offer customized financial accountability solutions. Trust our expert guidance to meet your business compliance needs with finesse.

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