Comptroller of Maryland. Serving the People. Peter Franchot, Comptroller
Maryland Taxes
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Filing the Corporation Income Tax Return

Every Maryland corporation must file a corporation income tax return, using Form 500, even if the corporation has no taxable income or is inactive.

Corporation income tax returns can be filed electronically, using approved software. Talk to your software provider about electronic filing options.

Every other corporation that is subject to Maryland income tax law and has income or losses attributable to sources within Maryland must also file Form 500.

Corporations operating in Maryland and in one or more other states are subject to Maryland income tax if their Maryland activity exceeds the provisions for federal protection from state taxation. 15 U.S.C. Section 381 (P.L. 86-272) of the Interstate Commerce Act (P.L. 86-272) prescribes the extent of business activity required before states may impose income taxes.

A multistate corporation that operates in Maryland but is not subject to the Maryland income tax is not required to file, although a return reflecting an apportionment factor of zero may be filed for record purposes. We cannot accept letters sent in lieu of filing.

All financial institutions formerly subject to the financial institution franchise tax are subject to corporation income tax and have special apportionment rules. For more information, see Regulation 03.04.08 on COMAR Online.


Remember to enter your federal employer identification number (FEIN) on the Maryland corporation tax return and other forms.

Use Activity Code

Be sure to enter the business activity code number on Form 500.


Indicate the following on all correspondence and payments:

  • Corporate name
  • FEIN
  • Tax type
  • Tax year


Links for Corporations
Business Tax Types
Income Tax
Filing Information
  Estimated Corporation Tax Payment Information
  Apportionment Factor
  Business Tax Credits
  Filing Deadlines and Extensions
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