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Key September 2025 Tax Deadlines and Planning Tips

Stay ahead of the game with September 2025's crucial tax deadlines, including tip reporting and estimated tax payments. This September, ensure you're taking advantage of safe harbor rules, minimizing penalties, and strategically preparing for tax year 2026.

Fall 2025 and 2026 Tax Strategy

Proactive tax planning is essential. Contact our office to schedule a consultation to discuss tailored strategies.

September 10: Tip Reporting Obligation

If you’re an employee who received over $20 in tips in August, report these to your employer on IRS Form 4070 by September 10. Employers must withhold both FICA and income taxes from your wages. Insufficient regular wages will lead the employer to document uncollected amounts in box 8 of your W-2, payable when filing your annual return.

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September 15: Estimated Tax Payment Deadline

The third quarterly installment of 2025 individual estimated taxes is due. With a "pay-as-you-earn" tax system, options like payroll withholding, pension withholding, and estimated tax payments help meet this obligation.

  • Employees benefit from payroll withholding.
  • Retirees may choose pension withholding.
  • Self-employed individuals and others with non-withheld income use estimated tax payments.

Avoid the underpayment penalty—which is the federal short-term rate plus 3%—by making adequate prepayments. Federal law offers two safe harbor provisions:

  • Prepay 90% of the current year’s tax.
  • Prepay 100% of the prior year’s tax (110% for high AGI filers).

Illustrative Example: If your current tax is $10,000 and you've prepaid $5,600, you're short of the 90% safe harbor. Yet, if last year’s tax was $5,000 and you've prepaid $5,600, exceeding 110% of the prior year’s liability, the penalty is waived.

This emphasizes the critical nature of assessing your prepayments, especially after significant income changes, such as from stock sales, property sales, bonuses, or retirement. Timeliness in payments is crucial to meet safe harbor standards. For assistance with your estimates, reach out to our office promptly.

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Note: Some states have unique de minimis amounts and safe harbor guidelines. Contact us for specifics on state rules.

Adjustments for Weekends and Holidays

If a deadline falls on a weekend or holiday, the due date extends to the next business day.

Disaster Area Extensions

In federally declared disaster areas, deadlines may extend. For current designations and extended dates, refer to FEMA or IRS resources.

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