Business Income Tax

Filing and paying business taxes can be complicated. The Comptroller's Office is dedicated to making the process as simple and efficient as possible. This section contains all of the information, resources and tools business taxpayers will need to understand the tax. Follow the links below and at the bottom of each page of the section.

  • Learn about it! See the Tax Information section for all of the details including special situations, tax regulations (alerts and bulletins) and tax rates.
  • File it!The Filing Information section has all the information and resources you need to file business tax, including registration information for new filers, related forms, filing instructions and due dates.
  • Pay it! See the Payment Information section regarding the different payment methods available. If you miss a payment or fail to file a return see the Compliance Information section for details on penalties and liability.
  • Get your refund! You may be eligible for a refund of paid business tax if you meet the requirements. See Refund Information below for details.
  • Employer Withholding. See the Withholding Information section for filing information, withholding tables and guides, and year-end reconciliations.
  • Get help! For additional assistance, review the Frequently Asked Questions or Contact Information links.

Business Tax Updates

  • Bulk Upload of W-2's Employers and payroll providers can log into bFile and upload a W-2 text file.
  • Form 510C - effective tax year 2011. Form 510C is used by PTEs to file a composite income tax return on behalf of nonresident individual members. Do not file a composite return using Form 505. See Technical Bulletin 6 for additional details.

The Form 510, Pass-through Entity Tax Return, only will allow a refund if there are no nonresident members and the amount on line 13 of the return is zero.

Refund Claims

Generally, a claim for a refund (amended return) must be filed within 3 years from the date the original return was filed or within 2 years from the date the tax was paid, whichever is later. A return filed early is considered filed on the date it was due.

If the claim for refund resulted from an IRS adjustment or final decision of a federal court which is more than 3 years from the date of filing the return or more than 2 years from the time the tax was paid, a claim for refund must be filed within 1 year from the date of the adjustment or final decision.

A claim for refund based on a federal net operating loss carryback must be filed within 3 years after the due date of the return for the tax year of the net operating loss.


Effective tax year 2011, a pass-through entity may elect to file a composite Maryland income tax return Form 510C on behalf of qualified nonresident individual members. All members who qualify and elect to be included on the composite return must agree that the pass-through entity is their agent for the receipt of any refund or for payment of any tax due.

Reports and Statistics Regarding Income Tax

The following report(s) are part of a collection of monthly revenue reports published by the Comptroller's Office. For a full listing of monthly and annual reports, see Spotlight on Maryland Money.

General Fund Revenue Memorandum

Income Tax Monthly Comparative Revenue Statement: Comparative revenue statements of corporate income tax and personal income tax receipts.