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Connecticut Business State Tax Extension I Fiduciaries Filing Guide

Application for Extension of Time to File Connecticut Income Tax Return for Trusts and Estates  ·  Fiduciaries  ·  Business Filing Guide

Overview

Connecticut fiduciaries—including estates and trusts—are subject to state fiduciary income tax requirements, administered by the Connecticut | Department of Revenue Services. Connecticut grants an automatic extension tied to an approved IRS extension, making the process simple for businesses that have already filed IRS Form 8868.

Original Filing Deadline

• The original due date for the Connecticut Fiduciaries return is April 15, 2026. File or remit full payment by this date to remain in good standing.
• Extension Period & Extended Deadline
• Connecticut automatically grants an extension to file, provided you have obtained an approved federal extension from the IRS by filing IRS Form 8868. With a valid IRS extension, the Connecticut extended deadline becomes September 30, 2026. No separate state extension form is required—the federal extension serves as your Connecticut extension.

Payment Is Still Due by Original Deadline

The extension applies to filing only—it is not an extension to pay taxes owed. Any outstanding tax liability must be paid by the original due date of April 15, 2026 to avoid penalties and interest. Use the Connecticut | Online Tax Extension Payment to pay electronically. For mail-in payments, use Application for Extension of Time to File Connecticut Income Tax Return for Trusts and Estates and send to: Click here to access the payment portal

Late Filing and Payment Penalties

• Failure to File: $50 penalty, or 10% of the tax due, whichever is greater.
• Failure to Pay: $50 penalty, or 10% of the tax due, whichever is greater.

Best Practices

• Estimate and pay your Connecticut business tax by April 15, 2026 to avoid interest and penalties.
• File IRS Form 8868 with the IRS to secure your federal extension, which Connecticut automatically honors.
• Use the state online payment portal for fast, convenient electronic payment.
• Set a reminder to file your completed Connecticut Fiduciaries return by September 30, 2026.

Final Thoughts

• Connecticut's business tax extension is straightforward once your federal extension is approved. Pay 100% of any tax due by April 15, 2026 and file your Fiduciaries return by September 30, 2026.
• Quick Reference Table
• State Abbreviation
• CT
• State Name
• Connecticut
• Business Entity Type
• Fiduciaries
• Extension Status
• Approved with Federal Extension
• Return Due Date
• April 15, 2026
• Extended Due Date
• September 30, 2026
• Other Information
• Connecticut grants your business an automatic 6-month extension provided you have obtained an approved IRS extension. The extension is NOT an extension to pay any taxes you may have due. Tax payments are due by the original return due date.
• Online Payment
• Connecticut | Online Tax Extension Payment
• Payment Voucher Form
• Application for Extension of Time to File Connecticut Income Tax Return for Trusts and Estates
• State Payment Agency
• Connecticut | Department of Revenue Services
• Mailing Address with Payment
• Click here to access the payment portal
• Failure to File Penalties
• $50 penalty, or 10% of the tax due, whichever is greater.
• Failure to Pay Penalties
• $50 penalty, or 10% of the tax due, whichever is greater.

Working with a Tax Professional

Business tax returns are complex—a licensed CPA or Enrolled Agent can maximize deductions, ensure accurate calculations, and handle filing on your behalf. Here's how working with a TaxPro typically goes:

1. 1Get matched with a verified U.S.-based CPA or Enrolled Agent
2. 2Upload your business documents via secure drag-and-drop
3. 3Review and approve your return with upfront, transparent fees
4. 4Your TaxPro files your Connecticut return by September 30, 2026

Quick Reference Table

State Abbreviation	CT
State Name	Connecticut
Business Entity Type	Fiduciaries
Extension Status	Approved with Federal Extension
Return Due Date	April 15, 2026
Extended Due Date	September 30, 2026
Other Information	Connecticut grants your business an automatic 6-month extension provided you have obtained an approved IRS extension. The extension is NOT an extension to pay any taxes you may have due. Tax payments are due by the original return due date.
Online Payment	Connecticut | Online Tax Extension Payment
Payment Voucher Form	Application for Extension of Time to File Connecticut Income Tax Return for Trusts and Estates
State Payment Agency	Connecticut | Department of Revenue Services
Mailing Address with Payment	Click here to access the payment portal
Failure to File Penalties	$50 penalty, or 10% of the tax due, whichever is greater.
Failure to Pay Penalties	$50 penalty, or 10% of the tax due, whichever is greater.