Maryland Form 500D is the declaration corporations and partnerships use to pay Maryland income tax in four quarterly installments when they expect to owe more than $1,000 for the year.1Maryland General Assembly. Maryland Code Tax-General 10-816 It’s a single-page worksheet: estimate your annual Maryland tax, divide by four, and send a copy with payment on the 15th day of the 4th, 6th, 9th, and 12th months of your tax year.
Who Has to File
Under Maryland Tax-General ยง 10-816, every corporation and every partnership that reasonably expects its Maryland income tax to exceed $1,000 for the taxable year must file a declaration of estimated income tax.1Maryland General Assembly. Maryland Code Tax-General 10-816 It doesn’t matter whether the entity was formed in Maryland or is a foreign business registered to do business here. If your expected tax is $1,000 or less, you can skip estimated payments and settle the balance when you file your annual Form 500.
Filling Out the Worksheet
Before you start, pull together your Federal Employer Identification Number, the corporation’s legal name as it appears on the Articles of Incorporation (plus any “Trading As” name), and the beginning and ending dates of the tax year. The tax year on Form 500D must match the one on your federal return.2Comptroller of Maryland. Maryland Form 500D Corporation Declaration of Estimated Income Tax
The worksheet has three lines. On Line 1, enter the taxable income you expect for the full tax year. On Line 2, multiply Line 1 by 8.25%, Maryland’s flat corporate income tax rate, then subtract any tax credits you expect to claim; that’s your estimated income tax for the year.3Tax Foundation. State Corporate Income Tax Rates and Brackets, 2026 On Line 3, divide Line 2 by four. That’s your quarterly installment.
If your estimate doesn’t change after the first quarter, you don’t need to redo the math; just send the same amount with each voucher. Keep copies of every voucher you submit.
When Payments Are Due
Installments are due on the 15th day of the 4th, 6th, 9th, and 12th months after the start of your tax year, and at least 25% of your total estimated tax must be paid by each deadline.4Comptroller of Maryland. Maryland Form 500D – Corporation Declaration of Estimated Income Tax
For a calendar-year corporation, that means:
- 1st installment: April 15
- 2nd installment: June 15
- 3rd installment: September 15
- 4th installment: December 15
Fiscal-year filers count from the start of their own tax year. A corporation with a July 1 fiscal-year start, for example, would owe installments on October 15, December 15, March 15, and June 15. When a deadline lands on a weekend or state-recognized holiday, it shifts to the next business day.
How to Pay
Online
The Comptroller’s online portal, Maryland Tax Connect, accepts estimated income tax payments electronically and lists “Make an Estimated Payment” as a primary function on its landing page.5Maryland Tax Connect. Maryland Tax Connect It has replaced the older bFile portal for most business tax filings, so prior bFile users will need to move to Maryland Tax Connect.6Comptroller of Maryland. bFile – Select Application
By Mail
If you’re filing on paper, mail the completed Form 500D with a check or money order payable to the Comptroller of Maryland to:
Comptroller of Maryland
Revenue Administration Division
110 Carroll Street
Annapolis, MD 21411-00014Comptroller of Maryland. Maryland Form 500D – Corporation Declaration of Estimated Income Tax
Write your FEIN, the tax type, and the tax year beginning and ending dates on the check in blue or black ink. Leaving any of that off will delay processing.
Changing Your Estimate Mid-Year
If business conditions shift and your original projection no longer looks right, recalculate using the same worksheet and adjust the next installment to account for any overpayment or underpayment from earlier quarters. Each remaining installment must still cover at least 25% of your amended annual estimate.2Comptroller of Maryland. Maryland Form 500D Corporation Declaration of Estimated Income Tax
One important boundary: the annualized income installment method, which the IRS allows on the federal side to soften underpayment penalties for businesses with seasonal income, is not permitted for Maryland corporate estimated tax.4Comptroller of Maryland. Maryland Form 500D – Corporation Declaration of Estimated Income Tax You divide by four regardless of when income actually arrives.
Short Tax Years
A corporation with a tax period shorter than a full year, due to mid-year incorporation, a merger, dissolution, or a change in accounting period, still owes estimated tax unless the short period is less than four months. If the period is four months or longer, the total estimated tax required is the same as a regular year (90% of the current short-year tax or 110% of the prior year’s tax, whichever method you choose), but you divide by the number of quarterly installment dates that fall within the short period rather than by four.4Comptroller of Maryland. Maryland Form 500D – Corporation Declaration of Estimated Income Tax
What Underpayment Costs
Maryland charges interest on unpaid tax from the original due date until the day you pay.7Maryland General Assembly. Maryland Code Tax-General 13-601 – Unpaid Tax For the 2025 tax year, the annual rate is 10.8133%, roughly 0.9% per month.8Comptroller of Maryland. What’s New for the 2026 Tax Filing Season (2025 Tax Year) Late-payment penalties can reach as high as 25% of the tax owed.9Comptroller of Maryland. Tax Guidance – Penalty and Interest Charges
These charges apply whenever you miss a deadline or pay less than the required 25% installment. The Comptroller calculates the deficiency for each quarter independently, so underpaying one installment triggers interest on that specific shortfall even if later payments arrive on time. Because the annualized method isn’t available, basing your estimate on 110% of last year’s tax is the safer path if your income is volatile.
Reconciling on Form 500 at Year-End
Everything you paid with Form 500D during the year, together with any overpayment credited from the prior year, is reported on Line 15a of Maryland Form 500, the annual Corporation Income Tax Return.10Comptroller of Maryland. Maryland Form 500 Corporation Income Tax Return The return compares total tax on Line 14 against total payments and credits on Line 15i to produce either a balance due on Line 16 or an overpayment on Line 17.
If your estimated payments came in higher than your actual tax, you can take a refund or apply the overpayment as a credit toward the following year’s estimated tax. Applying it forward shrinks your first installment next year. Either way, keeping clean records of each Form 500D payment (amount, date, and confirmation number for electronic payments) makes year-end reconciliation straightforward and gives you documentation if the Comptroller questions a payment later.