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The Smarter Startup
March 11, 2025

Key Q2 2025 Tax Deadlines for Startups

Q2 tax deadlines are coming fast. Stay ahead of key filings, avoid penalties, and keep your startup on track with this essential guide.

As the second quarter of 2025 approaches, startups must stay ahead of crucial Q2 tax deadlines to maintain compliance and optimize financial planning. Missing key filings can lead to costly penalties, cash flow disruptions, and compliance risks. Below, we highlight the most important tax deadlines for Q2 and outline the necessary steps your startup should take.

Also see Burkland’s roundup of important 2025 tax deadlines for startups. It includes federal filing dates as well as key deadlines for San Francisco, New York, and Seattle throughout the year.

April 15: Income Tax Filings and Estimated Tax Payments

  • Federal and State Income Tax Returns (Individuals & Corporations): C-corporations, individuals, and trusts must file their federal and state income tax returns or request an extension.
    • Why It Matters: Filing on time avoids IRS penalties and interest on unpaid taxes.
    • Steps to Take: Ensure all financial records are up to date and work with a tax advisor to finalize and file your return or request an extension if needed.
  • Federal Quarterly Estimated Taxes (Q1): Startups that expect to owe $1,000 or more in taxes for the year must make their first estimated quarterly payment.
    • Why It Matters: Paying quarterly helps avoid underpayment penalties and interest charges.
    • Steps to Take: Calculate estimated taxes based on projected annual income and submit payment via the IRS online payment portal.
  • FinCEN 114 – FBAR (Foreign Bank Account Report): While extensions are available, those with foreign bank accounts exceeding $10,000 at any time during the year must file this report.
    • Why It Matters: Non-compliance can result in significant fines and penalties.
    • Steps to Take: Review foreign account balances and work with a compliance expert if necessary.

April 30: Sales & Use Tax and Payroll Tax Credit Filings

  • Quarterly Sales and Use Tax Filing: Businesses with taxable sales must report and remit Q1 sales and use tax.
    • Why It Matters: Non-payment can lead to penalties and potential audits.
    • Steps to Take: Verify sales tax collection for Q1 and file using state tax portals.
  • R&D Tax Credit (Form 941): Eligible startups can claim the Research and Development Tax Credit against payroll taxes for Q1.
    • Why It Matters: This credit helps startups reduce payroll tax liability and improve cash flow.
    • Steps to Take: Maintain proper documentation of R&D activities and expenses, and submit Form 941 on time.

May 15: Exempt Organization Filings

  • Form 990 Series – Tax-Exempt Organizations: Nonprofits and tax-exempt organizations must file their annual returns to maintain tax-exempt status.
    • Why It Matters: Failure to file for three consecutive years results in automatic revocation of tax-exempt status.
    • Steps to Take: Confirm eligibility and prepare required documents for submission.
  • Form 8868 – Extension Application for Tax-Exempt Organizations: Organizations needing extra time can file for an extension.
    • Why It Matters: Allows additional time to compile necessary records and prevent filing errors.
    • Steps to Take: Submit Form 8868 before the deadline to extend filing.

May 31: San Francisco Business Registration Renewal

  • Renew Business Registration: Businesses operating in San Francisco must renew their business registration.
    • Why It Matters: Maintaining an active registration prevents business penalties or suspension.
    • Steps to Take: Complete the renewal through the San Francisco city tax portal.

June 2: Delaware Franchise Tax

  • Delaware Quarterly Estimated Franchise Tax Payment: Delaware-incorporated startups must make their Q2 estimated tax payment.
    • Why It Matters: Ensures compliance with state regulations and prevents penalties.
    • Steps to Take: Review franchise tax calculations and submit payments via Delaware’s online tax portal.

June 16: Federal & State Estimated Tax Payments

  • Federal Quarterly Estimated Taxes (Q2): The second quarterly estimated tax payment is due for businesses and individuals with tax obligations.
    • Why It Matters: Staying current with estimated taxes helps avoid IRS penalties and interest charges.
    • Steps to Take: Adjust estimated payments based on Q1 earnings and projected annual income.
  • California Quarterly Estimated Taxes (Q2): Startups operating in California must make their quarterly tax payment to the state.
    • Why It Matters: Prevents late fees and interest accumulation on unpaid state taxes.
    • Steps to Take: Use the California Franchise Tax Board’s online portal to submit payment.

June 30: Mid-Year Tax Review & Compliance Check

  • While not a required deadline, startups should take this time to review their tax compliance, track expenses, and adjust tax planning strategies.
    • Why It Matters: Catching tax issues early can prevent last-minute stress and unexpected liabilities.
    • Steps to Take: Work with a tax advisor to assess tax obligations, optimize deductions, and update financial records.

Tax Planning Tips for Startups

  1. Stay Proactive: Set reminders for tax deadlines and file early when possible.
  2. Leverage Tax Credits: Take full advantage of R&D credits and other tax incentives.
  3. Monitor Cash Flow: Ensure estimated tax payments align with revenue and expenses.
  4. Consult Experts: Work with experienced tax professionals to prepare filings and avoid compliance issues.

By staying ahead of these important Q2 tax deadlines, your startup can maintain compliance, avoid penalties, and focus on strategic growth in 2025.