October not only brings refreshing autumn days but also significant business tax deadlines crucial for compliance. From corporate filings to retirement contributions, ensure you are on track to meet these important dates and avoid penalties.

October 15 – Corporate Tax Filings

Corporations need to file their 2024 calendar year income tax return (Form 1120) and settle any outstanding tax, interest, and penalties by this date. This deadline is only applicable if an automatic 6-month extension was secured by April 15.

October 15 – Payroll Tax Deposits

Employers following monthly deposit rules must complete their Social Security, Medicare, and withheld income tax deposits for September 2025 by October 15. This also stands as the due date for nonpayroll withholding deposits for September under the same monthly rule.

October 15 – Establish a Keogh Retirement Account

Self-employed individuals with a 6-month extension for filing their 2023-2024 tax return have until October 15, 2025, to set up a Keogh Retirement Account to qualify for 2024 contributions.

October 15 – SEP and Keogh Contributions

This marks the last opportunity to contribute to a SEP or Keogh plan for the 2024 calendar year if the individual or entity has extended the tax return filing to this date.

October 31 – Form 941 & Payroll Deposits

Employers must file Form 941 for the third quarter of 2025 and deposit any remaining taxes under the accuracy of deposit rules by October 31. If the quarterly tax liability is below $2,500, full payment with the filed return is permissible. Taxes deposited for the quarter fully and timely extend the return filing deadline to November 10.

October 31 – Tax Deposits for Small Employers

Small employers with annual liabilities of $2,500 or more, but under $2,500 for the third quarter, should deposit any undeposited taxes by this date.

October 31 – Federal Unemployment Tax (FUTA)

Ensure the deposit of owed unemployment taxes through September if they exceed $500.

Considerations for Weekends & Holidays

Due dates falling on weekends or legal holidays automatically extend to the subsequent business day that is not a holiday.

Filing Extensions for Disaster Areas

Designations of disaster areas can extend filing deadlines. Confirm if a location has received such a designation and the related deadlines by visiting:
FEMA: https://www.fema.gov/disaster/declarations
IRS: https://www.irs.gov/newsroom/tax-relief-in-disaster-situations