Received a Letter from the Maryland Comptroller? The 30-Day Deadline

A letter from the Maryland Comptroller means the state’s tax authority needs something from you — money, documents, or confirmation that you are who you say you are. Which of those it wants depends on the type of notice, and the type of notice determines how quickly you have to act. Most letters carry a 30-day response window that starts the day the letter is mailed, and letting that window close can cost you the right to appeal, add penalties and interest, and trigger enforcement actions like tax liens and wage garnishments.¹

Identify Which Notice You Received

Before you do anything else, figure out what the letter is. The Comptroller sends five common types, and each calls for a different response.

A Notice of Assessment is a bill. It says the Comptroller has calculated additional tax owed — usually from a math error, unreported income, or a mismatch between your Maryland return and your federal return — and the balance includes tax, interest, and a late-payment penalty.²

An Information Request or Audit Notice asks for documentation to verify something on your return. It might be a single-document ask or the start of a formal audit. Common audit targets are Schedule C business expenses, itemized deductions, multi-state income apportionment, and subtraction modifications claimed under Maryland law.

A Refund Adjustment or Denial tells you your refund was reduced or rejected. This often happens when the state disallows a subtraction modification from federal adjusted gross income or finds a discrepancy with your federal return.³

A Collection Notice is an escalation. The debt is already established, and the Comptroller is preparing to use enforcement tools such as tax liens and wage garnishments.

An Identity Verification Request means the Comptroller suspects someone may have filed a fraudulent return using your information and needs you to confirm your identity before your legitimate return is processed. These are common during filing season.

The 30-Day Deadline

Every Comptroller letter includes a Notice Number, an Account Number, and a response deadline printed on the first page. That deadline is almost always 30 days from the mailing date, and missing it has real consequences. If you’re contesting a refund denial and respond late, the denial becomes final with no further recourse. If you’re contesting an assessment and respond late, you lose your right to a hearing; a hearing officer may still look at documents you submit, but the resulting decision cannot be appealed.¹

Write the deadline down. Pull the tax return the notice references and the supporting records that go with it — W-2s, 1099s, receipts, bank statements. Organize what you send by line item. A disorganized submission slows the process and invites further scrutiny.

How to Respond

Look for response instructions on the notice itself. Some letters let you respond through the Maryland Tax Connect portal. Others require documents sent by mail, and certified mail with a return receipt is worth the small cost because it proves you responded on time.

If you want to talk to someone before you respond, the Comptroller’s taxpayer services division answers questions by phone at 410-260-7980 or 1-800-638-2937, Monday through Friday from 8:30 a.m. to 4:30 p.m. You can also open a case through the MyCOMConnect customer service portal or schedule an appointment at one of the 11 branch offices across the state.⁴

For an audit or information request, provide original source documents cross-referenced to the specific line items they support. Maryland requires that your state return match your federal return, and everything is subject to verification, so expect the auditor to ask for your federal Form 1040 alongside the Maryland return.⁵ After the auditor reviews what you sent, you’ll receive a Notice of Proposed Assessment laying out the proposed changes and recalculated tax. That proposed assessment is not final — there’s a window to push back informally, provide more evidence, or negotiate directly with the auditor. Most disputes that are going to be resolved without a formal appeal are resolved here.

What Delay Costs You

Maryland charges 9% annual interest on unpaid tax, running from the original due date of the return until the balance is paid in full.⁶ The statutory rate is the greater of 9% or three points above the average prime rate, and 9% has been the floor since 2023. Interest keeps compounding even if you’re on a payment plan or in the middle of an appeal.

Penalties stack on top of the interest. Missing the payment due date triggers a late-payment penalty. Missing the filing deadline triggers a separate and larger penalty. An assessment sent after you’ve been warned and haven’t responded will typically carry both.²

If a collection notice has already arrived, the Comptroller can file a certificate of tax lien with the county recorder of deeds to attach your real and personal property, or with the circuit court to operate like a court judgment.⁷ A wage lien redirects your pay above the exempt amount to the state until the debt is paid off.⁸ The way to keep enforcement from escalating is to contact the Collections Division and acknowledge the debt, even if you can’t pay it all right away.

If You Owe the Money but Can’t Pay

Installment Agreements

An installment agreement lets you pay a Maryland tax debt monthly instead of in a lump sum. You can apply online through the Comptroller’s individual payment agreement portal for personal income tax liabilities. The Collections Division looks at your finances and sets terms. Interest and penalties keep running on the unpaid balance, so you’ll pay more overall than you would have paid upfront. Missing payments or failing to file future returns on time defaults the agreement and puts the full remaining balance back into the enforcement pipeline.

Offer in Compromise

If you genuinely can’t pay in full even over time, Maryland’s Offer in Compromise program lets you propose settling for less. The bar is high, and the program has strict eligibility rules:⁹

At least two years must have passed since you became liable for the tax.
You must be current on all required filings — the current year plus the prior six tax years for individual income tax.
No issue related to the liability can be under appeal.
You cannot be in an active bankruptcy proceeding.
For business tax debts or officer assessments, the business must be closed.

The application uses Form MD 656 together with Form MD 433-A, a detailed financial statement. Submit them together; the Comptroller returns a Form MD 656 that arrives without the financial statement. The state uses your assets, income, and future earning capacity to set the minimum it will accept. If your first offer is too low but the Comptroller agrees you can’t pay in full, you’ll be told what amount would work.⁹

Penalty Waiver

The Comptroller can waive penalties for “reasonable cause.”¹⁰ The statute doesn’t define the term, so the Comptroller has discretion. Serious illness, a natural disaster, reliance on a tax professional who made an error, or a death in the family are the kinds of circumstances that tend to support abatement. A waiver only removes the penalty; the underlying tax and accrued interest are still due.

There is no formal waiver application form. Send a written explanation of the circumstances with supporting documentation (medical records, insurance claims, correspondence with a preparer) either as a standalone letter to the Comptroller or as part of your response to the assessment notice.

If You Disagree With the Notice

Start informally. During the audit or proposed-assessment phase, you can dispute findings and offer more evidence directly to the auditor. Once the assessment becomes final, you’re in the formal appeals process, and the 30-day clock restarts on the notice of final determination.

File a written protest with the Hearings and Appeals Section within 30 days of the mailing date on that notice. Include your name, current address, email, phone number, the tax years being appealed, and your Social Security number or business identification number. Mail it to:

Comptroller of Maryland
Attn: Hearings & Appeals
7 St. Paul Street, Room 210
Baltimore, Maryland 21202¹

A hearing officer acts as a neutral decision-maker. Before a formal hearing is scheduled, the officer may contact you about settling the dispute or resolving it on documents. If nothing is agreed, you get a hearing where you present evidence and arguments, and the officer issues a written notice of final determination that upholds, reduces, or eliminates the assessment.¹

If the hearing officer rules against you, the next stop is the Maryland Tax Court, an independent body that conducts a fresh de novo review. File a petition within 30 days of the notice of final determination, stating the facts supporting your appeal and each question you want reviewed.¹¹ Either party can appeal a final Tax Court order to the circuit court for judicial review.¹² By that stage, most taxpayers work with a tax attorney.

How Far Back the Comptroller Can Go

The Comptroller generally has three years from the later of your return’s filing date or its due date to assess additional income tax. Once that window closes, the state normally can’t come back and say you owe more.¹³ Several situations override the three-year limit and let the Comptroller assess at any time:

Filing a false return with intent to evade tax.
A willful attempt to avoid paying.
Not filing a required return at all.
Filing a return that is materially incomplete.
Failing to report federal audit adjustments to Maryland within the required period.

After a valid assessment is made, the state has 10 years to collect on it. If you received a notice for a tax year that looks too old, check whether any of these exceptions apply before assuming the assessment is out of time.

Identity Verification Letters and Scam Letters

If the letter is an identity verification request, the Comptroller has flagged a return filed under your name or Social Security number as potentially fraudulent. Respond promptly using the instructions in the letter. Your legitimate return can’t be processed until verification is finished. The Comptroller has stated that a fraudulent filing in your name will not affect your valid return and that the office takes steps to secure your personal and financial information.⁴

Be careful with any communication that demands immediate payment or threatens arrest. The Comptroller doesn’t operate that way. If something feels off, don’t engage with the message. Call 410-260-7980 or 1-800-638-2937 to verify whether the communication is real.

When to Bring in a Professional

For a small balance from a math error or a simple document request, most people can handle the response themselves. Audit notices, proposed assessments with sizable balances, and collection actions are where a CPA or tax attorney familiar with Maryland procedure earns their fee. The audit stage, before an assessment becomes final, is where the most flexibility exists. Options narrow and costs rise once a case moves into formal appeals or Tax Court.

To authorize someone to act for you, file Form 548, Power of Attorney and Declaration of Representative, with the Comptroller. The form requires the representative’s professional credentials — an attorney’s license number, a CPA’s license number, an enrolled agent’s enrollment card number, or a Maryland registered tax preparer’s registration number.¹⁴ The Comptroller also accepts a durable power of attorney or any other form authorized under Maryland law. Once Form 548 is on file, your representative can communicate with the Comptroller, attend hearings, and access your tax account information without you present.

1
Comptroller of Maryland. Frequently Asked Questions about Hearings and the Appeals Process
2
Comptroller of Maryland. Tax Tip 36 If You Get a Notice for Personal Income Tax
3
Maryland General Assembly. Maryland Tax General Code Section 10-207 – Subtractions From Federal Adjusted Gross Income in General
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Comptroller of Maryland. Comptroller Lierman Encourages Marylanders to Look Out for Scams This Tax Season
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Comptroller of Maryland. iFile – Help – General Requirements
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Maryland General Assembly. Maryland Tax General Code Section 13-604 – Interest Rates
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Comptroller of Maryland. Find Tax Liens
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Maryland General Assembly. Maryland Tax General Code Section 13-811 – Enforcement by Wage Lien for Income Tax
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Comptroller of Maryland. Offer in Compromise FAQs
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Maryland General Assembly. Maryland Tax General Code Section 13-714 – Waiver of Penalty
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Maryland Tax Court. Procedures of the Maryland Tax Court
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Maryland General Assembly. Maryland Tax General Code Section 13-532 – Judicial Review
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Maryland General Assembly. Maryland Tax General Code Section 13-1101
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Maryland Comptroller. Maryland Form 548 Power of Attorney Instructions