Connect with a TaxPro →

Maryland Business State Tax Extension I C Corporations Filing Guide

Online only  ·  C Corporations  ·  Business Filing Guide

Overview

Maryland C Corporations are subject to state corporate income tax requirements, administered by the Comptroller of Maryland. An extension of time to file requires submitting a state extension request before the original deadline.

Original Filing Deadline

• The original due date for the Maryland C Corporations return is April 15, 2026. File or remit full payment by this date to remain in good standing.
• How to Request a Filing Extension
• To extend your Maryland C Corporations filing deadline, you must submit the state extension form by the original due date of April 15, 2026. If approved, the extended filing deadline is November 15, 2026.

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 Maryland | Online Tax Extension Payment to pay electronically. For mail-in payments, use Online only and send to: Online only

Late Filing and Payment Penalties

• Failure to File: Up to 25% of the unpaid tax.
• Failure to Pay: Up to 25% of the unpaid tax.

Best Practices

• Estimate and pay your Maryland business tax by April 15, 2026 to avoid interest and penalties.
• Use the state online payment portal for fast, convenient electronic payment.
• Set a reminder to file your completed Maryland C Corporations return by November 15, 2026.

Final Thoughts

• Unlike states with automatic extensions, Maryland requires you to proactively request an extension. Submit your request before April 15, 2026 and file your return by November 15, 2026.
• Quick Reference Table
• State Abbreviation
• MD
• State Name
• Maryland
• Business Entity Type
• C Corporations
• Extension Status
• Action Required
• Return Due Date
• April 15, 2026
• Extended Due Date
• November 15, 2026
• Other Information
• Maryland REQUIRES that you file Form 500E by the due date of your return for a 7-month automatic extension. Extension may be filed online provided you've previously filed a business tax return. Fiduciary extensions cannot be filed online.
• Online Payment
• Maryland | Online Tax Extension Payment
• Payment Voucher Form
• Online only
• State Payment Agency
• Comptroller of Maryland
• Mailing Address with Payment
• Online only
• Failure to File Penalties
• Up to 25% of the unpaid tax.
• Failure to Pay Penalties
• Up to 25% of the unpaid tax.

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 Maryland return by November 15, 2026

Quick Reference Table

State Abbreviation	MD
State Name	Maryland
Business Entity Type	C Corporations
Extension Status	Action Required
Return Due Date	April 15, 2026
Extended Due Date	November 15, 2026
Other Information	Maryland REQUIRES that you file Form 500E by the due date of your return for a 7-month automatic extension. Extension may be filed online provided you've previously filed a business tax return. Fiduciary extensions cannot be filed online.
Online Payment	Maryland | Online Tax Extension Payment
Payment Voucher Form	Online only
State Payment Agency	Comptroller of Maryland
Mailing Address with Payment	Online only
Failure to File Penalties	Up to 25% of the unpaid tax.
Failure to Pay Penalties	Up to 25% of the unpaid tax.