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Essential October 2025 Tax Deadlines for Businesses

As we embrace the crisp autumn breeze, October brings with it pivotal tax deadlines for businesses, from corporate tax filings to retirement plan contributions. Staying on top of these key dates ensures compliance and helps avoid costly penalties.

October 15 - Corporate Tax Filing

File your 2024 calendar year income tax return using Form 1120. Ensure you pay any pending tax, interest, and penalties by this date if you obtained a 6-month extension by the previous April 15.Image 2

October 15 - Social Security, Medicare, and Withheld Income Tax

Employers following the monthly deposit rules must deposit Social Security, Medicare, and withheld income tax for September 2025 by October 15. This also includes the nonpayroll withholding deposit due on the same date under the monthly deposit rules.

October 15 - Nonpayroll Withholding

Ensure to deposit the taxes for payments made in September if you follow the monthly deposit rule.

October 15 - Last Day to Establish a Keogh Account for 2024

Entrepreneurs who received an automatic 6-month extension to file their 2023 tax returns have until October 15, 2025, to establish a Keogh Retirement Account for 2024.Image 1

October 15 - SEP IRA & Keogh Contributions

The deadline to contribute to SEP or Keogh retirement plans for the 2024 calendar year, provided your tax return is extended through October 15.

October 31 - Quarterly Tax Filings

File Form 941 for the third quarter of 2025. Deposit or pay any undeposited taxes under the accuracy of deposit rules. If your tax liability is under $2,500, you may pay it in full with a timely filed return. Deposited taxes for the quarter can delay filing until November 10.Image 3

October 31 - Small Employer Tax Deposits

Small employers must deposit any undeposited tax if their 2025 liability is $2,500 or more but less than $2,500 for the third quarter.

October 31 - Federal Unemployment Tax (FUTA)

Deposit owed taxes through September if they surpass the $500 threshold.

Weekends & Holidays:

If a deadline falls on a weekend or legal holiday, it is extended to the next business day that is not a legal holiday.

Disaster Area Extensions:

Natural disasters sometimes disrupt regular schedules. Discover if your area is designated a disaster area and learn about extended filing deadlines. For more details, check these resources:
FEMA: FEMA Disaster Declarations
IRS: IRS Tax Relief in Disaster Situations

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