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Essential Business Tax Deadlines for October 2025

The vibrant colors of autumn not only signal the arrival of cooler days but also remind businesses of crucial tax deadlines. From filing corporate taxes to managing payroll obligations, staying informed about these key dates is vital to ensure compliance and avoid penalties.

October 15 - Corporate Tax Filings

For corporations on a calendar year, October 15 marks the deadline to file the 2024 income tax return (Form 1120) and settle any outstanding taxes, interest, and penalties. This due date applies if an automatic 6-month extension was secured by April 15.

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October 15 - Social Security, Medicare, and Withholding Taxes

If you're an employer adhering to monthly deposit rules, October 15 is your deadline to deposit Social Security, Medicare, and withheld income taxes for September 2025. The same applies to nonpayroll withholding deposits for September.

October 15 - Keogh Account Setup and Contributions

For those who received an automatic filing extension, October 15, 2025, is the last day to establish a Keogh Retirement Account aimed for 2024 contributions. Additionally, it is the final opportunity to contribute to SEP or Keogh plans for 2024 if your tax filings are extended to October 15.

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October 31 - Payroll and Unemployment Taxes

The end of October demands action on several fronts. File Form 941 by October 31 for the third quarter of 2025. Ensure any undeposited tax is covered, particularly if underaccuracy of deposit penalties, unless taxes were deposited fully and on time, allowing extra filing time until November 10. For small employers, deposit any taxes due if liabilities are $2,500 or more for the year but under $2,500 for the quarter. Additionally, employers must deposit the Federal Unemployment Tax if it exceeds $500 through September.

Important Considerations: Weekends, Holidays, and Disasters

Weekend and Holiday Rule: Should a deadline fall on a weekend or a legal holiday, it automatically shifts to the next business day that is not itself a holiday.

Disaster Area Extensions: When areas are declared disaster zones, due dates may be extended. Verify if your region qualifies by visiting the following resources:
FEMA: https://www.fema.gov/disaster/declarations
IRS: https://www.irs.gov/newsroom/tax-relief-in-disaster-situations

Ensure you mark these critical dates in your calendar to manage your business's tax responsibilities efficiently, thereby maximizing your focus on growth and innovation.

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