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Key Tax Deadlines: September 2025

As we approach September 2025, it's crucial to stay informed about important tax deadlines, including tip reporting and the third installment of estimated tax payments. This guide will help you understand safe harbor rules, avoid penalties, and optimize your tax strategy for 2026.

Tax Planning for Fall 2025 and Beyond

Tax planning is an ongoing process. We encourage you to contact our office to schedule a personalized consultation.

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September 10 - Tip Reporting Deadline

Employees earning tips must report them to their employer using IRS Form 4070 by September 10, if they received more than $20 in tips during August. Employers are required to withhold FICA and income taxes on these tips. If insufficient wages are available for withholding, the employer will document the uncollected amount in box 8 of your W-2, which you will pay when filing your annual return.

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September 15 - Estimated Tax Payment Due

The third quarter estimated tax payment for 2025 is due. Our "pay-as-you-earn" tax system supports compliance through payroll withholding, pension withholding, and estimated tax payments for those with untaxed income sources.

To avoid an underpayment penalty, taxpayers must meet safe harbor benchmarks. This penalty adds three percentage points to the federal short-term rate and is calculated quarterly.

Federal tax regulations offer pathways to avoid penalties, including avoiding penalties if the underpayment is below $1,000 or by leveraging safe harbor rules:

  • Pay at least 90% of the current year’s tax liability.
  • Match 100% of the previous year’s tax, increasing to 110% if your AGI exceeds $150,000 ($75,000 filing separately).
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Example Scenario:

Consider a tax liability of $10,000, with prepayments of $5,600 leaving $4,400 due. The 90% safe harbor requires $9,000; thus, a shortfall would mean a penalty unless the previous year's tax was $5,000, meeting the 110% safe harbor at $5,500.

This highlights the importance of sufficient prepayments, especially with significant income changes, such as asset sales, bonuses, or retirement. Ensure that each estimated installment is timely to avoid penalties. For questions about your safe harbor estimates, contact our office promptly.

Caution: State safe harbor rules may vary. Please consult our office for specific guidance.

Weekends & Holidays Impact:

If a due date falls on a weekend or legal holiday, it extends to the next business day that's not a holiday.

Disaster Area Filing Extensions:

In designated disaster areas, tax deadlines may be extended. For updates, visit FEMA's disaster declarations and the IRS disaster relief page.

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