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Mississippi Business State Tax Extension I Fiduciaries Filing Guide

Form 83-180 | Application for Automatic Extension  ·  Fiduciaries  ·  Business Filing Guide

Overview

Mississippi fiduciaries—including estates and trusts—are subject to state fiduciary income tax requirements, administered by the Mississippi Department of Revenue. Mississippi 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 Mississippi Fiduciaries return is April 15, 2026. File or remit full payment by this date to remain in good standing.
• Extension Period & Extended Deadline
• Mississippi 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 Mississippi extended deadline becomes October 15, 2026. No separate state extension form is required—the federal extension serves as your Mississippi 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 Mississippi | Online Tax Extension Payment to pay electronically. For mail-in payments, use Form 83-180 | Application for Automatic Extension and send to: Department of Revenue P.O. Box 23191 Jackson, MS 39225-3191

Late Filing and Payment Penalties

• Failure to File: 5% per month, up to 25%.
• Failure to Pay: 0.5% of tax due, plus an additional 0.5% for each additional month, not to exceed 25%.

Best Practices

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

Final Thoughts

• Mississippi'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 October 15, 2026.
• Quick Reference Table
• State Abbreviation
• MS
• State Name
• Mississippi
• Business Entity Type
• Fiduciaries
• Extension Status
• Approved with Federal
• Return Due Date
• April 15, 2026
• Extended Due Date
• October 15, 2026
• Other Information
• Mississippi grants you an automatic 6-month extension to file your business tax return. The extension is NOT an extension to pay any taxes you may have due. Tax payments are due by the original return due date. Businesses are required to pay 100% of the tax due by the deadline or the return filing may be deemed to be late.
• Online Payment
• Mississippi | Online Tax Extension Payment
• Payment Voucher Form
• Form 83-180 | Application for Automatic Extension
• State Payment Agency
• Mississippi Department of Revenue
• Mailing Address with Payment
• Department of Revenue P.O. Box 23191 Jackson, MS 39225-3191
• Failure to File Penalties
• 5% per month, up to 25%.
• Failure to Pay Penalties
• 0.5% of tax due, plus an additional 0.5% for each additional month, not to exceed 25%.

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 Mississippi return by October 15, 2026

Quick Reference Table

State Abbreviation	MS
State Name	Mississippi
Business Entity Type	Fiduciaries
Extension Status	Approved with Federal
Return Due Date	April 15, 2026
Extended Due Date	October 15, 2026
Other Information	Mississippi grants you an automatic 6-month extension to file your business tax return. The extension is NOT an extension to pay any taxes you may have due. Tax payments are due by the original return due date. Businesses are required to pay 100% of the tax due by the deadline or the return filing may be deemed to be late.
Online Payment	Mississippi | Online Tax Extension Payment
Payment Voucher Form	Form 83-180 | Application for Automatic Extension
State Payment Agency	Mississippi Department of Revenue
Mailing Address with Payment	Department of Revenue P.O. Box 23191 Jackson, MS 39225-3191
Failure to File Penalties	5% per month, up to 25%.
Failure to Pay Penalties	0.5% of tax due, plus an additional 0.5% for each additional month, not to exceed 25%.