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Key Business Tax Deadlines for October 2025

October marks the beginning of the fall season, bringing with it a series of essential business tax deadlines that can’t be overlooked. From corporate tax filings to mandatory payroll deposits, it's crucial for businesses to be aware and prepare accordingly to avoid any penalties. Keep track of these pivotal dates to maintain compliance and safeguard your business interests.

October 15 - Corporate Tax Filings

October 15 is the deadline for corporations operating on a calendar-year basis to file their 2024 tax returns using Form 1120. Ensure that any outstanding taxes, interests, and penalties are settled, subject to a previously requested automatic 6-month extension granted by April 15.

October 15 - Payroll Tax Deposits

Employers adhering to monthly deposit rules must remit their Social Security, Medicare, and withheld income tax for September 2025 by this date. The same deadline applies for nonpayroll withholding deposits following the monthly rule.

October 15 - Nonpayroll Withholding

If your business follows the monthly deposit rule, this is the cut-off date to deposit taxes for payments processed in September.

October 15 - Keogh Accounts for Self-Employed

Self-employed individuals who secured an extension for their 2023/2024 tax filing until October 15, 2025, must establish a Keogh Retirement Account by this day to ensure eligibility for 2024 contributions.

October 15 - SEP IRA & Keogh Contributions

Those with extended tax returns can make their final SEP or Keogh retirement contributions for the 2024 fiscal year by this date.

October 31 - Quarterly Payroll Tax Filings

Form 941, detailing third-quarter payroll activities, is due. Ensure full payment of any undeposited taxes per the accuracy-of-deposit rules. If less than $2,500 is owed, you can submit payment with your return. Prompt deposits allow a postponed filing until November 10.

October 31 - Small Employer Obligations

Small employers need to deposit any unpaid taxes if their total liability for 2025 is at least $2,500 but under $2,500 for the third quarter.

October 31 - Federal Unemployment Tax

Deposit any Federal Unemployment Tax owing through September if it exceeds the $500 threshold.

Considerations for Weekends & Holidays

If a tax due date occurs on a weekend or legal holiday, it is deferred to the successive business day, when no holidays are observed.

Extensions for Disaster Areas

Businesses located in disaster-designated areas may benefit from extended tax deadlines. Visit the following resources for confirmations and additional information: FEMA and IRS.

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