Essential December 2025 Business Taxation Deadlines

December is a crucial month for businesses to address key taxation deadlines, including corporate estimated tax payments and mandatory payroll tax deposits. As the year concludes, ensure all necessary year-end financial actions are completed prior to closures on December 31st.

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December 15 - Corporations

The fourth quarterly installment of estimated taxes for corporations operating on a calendar year is due by this date.

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

Employers who adhere to the monthly deposit schedule must submit their contributions for Social Security, Medicare, and withheld income taxes for November 2025 by December 15. If applicable, nonpayroll withholding deposits for November are also due on this day.

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December 31 – Final Day of the Year Advisory

If critical year-end actions cannot be completed within a single day on December 31st, it is prudent to act earlier, especially given that some financial institutions might not be operating on the final day of the year.

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Weekends & Holidays Policy:

Any due date falling on a weekend or legal holiday automatically extends to the next business day that is not a holiday.

Disaster Area Filing Extensions:

In areas declared as disaster zones, tax filing dates will be extended. Check these resources to verify if your location is affected: FEMA declarations and IRS disaster relief.

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