Essential October 2025 Tax Deadlines for Businesses

October brings not only the briskness of fall but also critical tax deadlines that business owners must not overlook. Staying informed and proactive with these dates can help avoid costly penalties and ensure compliance with the IRS standards. Below is a detailed overview of the essential tax deadlines this month.

October 15 - Corporate Tax Return (Form 1120)

Corporations must file their 2024 calendar year income tax return using Form 1120 by this day, applicable only if the 6-month extension, requested by April 15, was approved. Timely payment of any due tax, interest, and penalties is essential.

October 15 - Payroll Tax Deposits

Employers subject to the monthly deposit rules must deposit Social Security, Medicare, and withheld income taxes for September 2025 by this date. Nonpayroll withholding deposits are also due, adhering to the monthly deposit rule.

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October 15 - Establishment of Keogh Retirement Plans

For self-employed individuals with a filing extension for their 2023–2024 tax return, October 15 marks the last opportunity to establish a Keogh Retirement Plan with contributions counted towards 2024.

October 15 - SEP IRA & Keogh Contributions

Ensure contributions to SEP or Keogh retirement plans for the 2024 calendar year are made if your tax return extension runs through this deadline.

October 31 - Quarterly Employer Taxes

File Form 941 for Q3 of 2025, ensuring any undeposited taxes are paid in accordance with the accuracy of deposit rules. Should your tax liability be under $2,500, you can settle this with your timely filed return. If deposits have been fully satisfied, Form 941 submission is extended to November 10.

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October 31 - Federal Unemployment Tax (FUTA)

Deposit any FUTA tax due through the end of September if the amount exceeds $500.

Flexible Deadlines on Weekends & Holidays

When a deadline lands on a weekend or legal holiday, the due date extends to the next business day.

Extensions for Disaster Areas

Taxpayers in designated disaster areas may receive filing extensions. Check FEMA and the IRS websites for up-to-date announcements regarding such designations.

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