Key December 2025 Tax Deadlines for Businesses

As the year winds down, it's crucial for businesses to stay on top of critical tax deadlines. December brings several important due dates, such as corporate estimated tax payments and payroll deposits. Additionally, this month serves as a reminder to complete your year-end financial tasks by December 31. Missing these deadlines could impact your business’s liquidity and tax compliance.

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December 15 - Corporations

The fourth installment of estimated tax payments for calendar year 2025 corporations is due. It’s essential to ensure accurate forecasts and sufficient cash flow to meet this obligation.

December 15 - Payroll and Nonpayroll Taxes

If you're an employer subject to monthly deposit rules, by December 15 you must deposit Social Security, Medicare, and withheld income taxes for November 2025. This is also the due date for nonpayroll withholding if applicable under monthly deposit rules.

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December 31 - Final Day of the Year

Consider acting before December 31 if your planned activities can't be completed in a single day, especially as some financial institutions might be closed or have modified hours.

Weekends & Holidays: Deadlines falling on a weekend or legal holiday extend to the next business day not designated as a holiday. Keep this in mind to avoid penalties and interest.

Disaster Area Extensions:

Understand that extensions are available in designated disaster areas. For updated information, visit:
FEMA: FEMA Disaster Declarations
IRS: IRS Disaster Tax Relief

Staying aware of these critical deadlines helps maintain your business’s financial health. Consider partnering with advisors like Lizza & Carullo CPA’s & Advisors for comprehensive support in navigating these requirements and aligning your financial strategies for growth. Our expert team provides clarity on obligations, while empowering your business to move confidently and strategically into the new year.

Gain Financial Clarity and Confidence
Partner with Lizza & Carullo CPA’s & Advisors to turn your numbers into strategy. Schedule a free consultation to discover how our outsourced CFO and client accounting services can help you improve cash flow, forecasting, and profitability — so you can plan ahead and grow with confidence.
Schedule Your Free Consultation
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