How to File a Massachusetts Abatement or Amended Return (Form CA-6)

Massachusetts Form CA-6, formerly the Application for Abatement/Amended Return, is no longer accepted by the Department of Revenue. Its replacement is Form ABT (Application for Abatement), which you file electronically through MassTaxConnect or mail to PO Box 7058, Boston, MA 02204.¹ If you still have a blank CA-6 in a file somewhere, don’t send it in. DOR will not process the discontinued form, and submitting it only delays your request.²

What Replaced the CA-6

DOR overhauled the abatement process in 2015.³ Form ABT now handles abatement requests, and amended returns are filed separately. If what you actually need to do is correct, amend, or update a return you already filed, file an amended return rather than Form ABT.¹

The underlying right to contest an assessment hasn’t changed. It still comes from Massachusetts General Laws Chapter 62C, Section 37, which lets any person who disagrees with a tax assessment apply in writing to the Commissioner for a reduction.⁴ MassTaxConnect is now the preferred channel, and if you were required to file the underlying return electronically, you must file the abatement electronically too.⁵

When You Have to File

Your Form ABT must reach DOR, electronically or by postmark, within whichever of these windows closes latest:⁵

Three years from the date you filed the return in question, or from its due date if you filed early.
Two years from the date the tax was assessed or deemed assessed.
One year from the date you paid the tax.
Two years from the date DOR determined you were personally liable as a responsible person.
If you and the Commissioner agreed to extend the assessment period under Chapter 62C, Section 27, the abatement window stays open at least as long as that extension.⁴

Miss all of them and DOR will reject the application without looking at the merits. For paper filings, the postmark date controls, not the date the envelope arrives.

Three Things DOR Checks First

Before DOR will consider the substance of your request, your application has to clear three gates:¹

You’ve already filed the return for the period you’re disputing. The exceptions are claims that no return was required and challenges to a responsible-person determination.
Your application is within the deadlines above.
You’ve documented your claim. DOR can deny the application outright if you haven’t given them enough to evaluate.

Information Form ABT Asks For

The online and paper versions collect the same core data. Have the following ready:¹

Identifiers: your SSN or FEIN, taxpayer name, spouse’s name and SSN if applicable, responsible person’s name and SSN if applicable, email addresses, the Letter ID from any notice you received, and your Account ID (entered without dashes).
Line 1, filing purpose: penalty appeal, audit dispute, motor vehicle sales/use tax, responsible person determination, motor vehicle excise, or other.
Line 2, tax type: personal income, withholding, sales/use, corporate excise, or another category.
Line 3, tax periods and amounts you want abated. If you need to list more than 12 periods, you have to file through MassTaxConnect.
Line 4, optional hearing request with the Office of Appeals.
Line 5, your explanation: the facts, the legal basis, and statutory references, with supporting documents attached.

Most abatement types require an Account ID; motor vehicle sales tax and deeds excise appeals are the exceptions.

Filing Online

MassTaxConnect is the fastest route, and it is mandatory if you were required to e-file the underlying return.⁶ After logging in, open the More… tab and choose File an Appeal from the Other Actions box. From there the prompts differ depending on whether you’re filing an audit appeal, an innocent spouse appeal, or a penalty waiver. Follow the on-screen instructions for your specific situation and attach supporting documents, including a Power of Attorney if someone else is representing you.

Filing on Paper

If you aren’t required to e-file, download Form ABT from mass.gov and mail it to:¹

Massachusetts Department of Revenue
PO Box 7058
Boston, MA 02204

Older references sometimes list PO Box 7010. That is the address on certain other DOR forms, not the current Form ABT. Use PO Box 7058 for abatement applications. Electronic filings are processed faster, so when both options are open to you, the online route is worth taking.⁵

If Someone Else Will Handle It for You

To let a tax professional, attorney, or family member act on your behalf, use Form M-2848 (Power of Attorney and Declaration of Representative). You either list each tax type and year or write “all tax types” and “all tax years” to set the scope.⁷ A signed M-2848 can go through MassTaxConnect, by email to POADOR@dor.state.ma.us, by fax, or to the DOR employee you’re working with. A parent acting for a minor child doesn’t need one.

Form M-2848 does not grant access to your MassTaxConnect account; that takes a separate third-party access authorization. Form ABT itself contains a narrow Power of Attorney that covers only the periods and issues in that specific appeal, so if your representative needs broader authority, file the full M-2848 as well.

What Happens After You File

Filing does not pause DOR collection activity. Keep paying assessed taxes on time to protect your appeal rights.⁸

There is no fixed processing time. DOR says tax type, time of year, the quality of your documentation, and the complexity of the issue all affect how long a review takes.⁵ This is where the six-month consent rule matters. By filing Form ABT, you automatically consent to let DOR take longer than six months to decide. If you don’t want to give that extension, attach a letter withdrawing consent when you file, or cross out the consent language in the signature section of the paper form. If DOR hasn’t acted within six months and you withdrew consent (or never gave it), the application is deemed denied, which starts your appeal clock.¹

DOR issues its decision as a formal Notice of Abatement Determination, by mail or through MassTaxConnect.

If DOR Denies the Abatement

A denial isn’t the end of the matter. You have 60 days from the date of the denial notice to file a petition with the Massachusetts Appellate Tax Board. That deadline is strict. The Appellate Tax Board cannot hear a case filed even one day late. Your petition can raise new legal theories, new facts, and new arguments that weren’t in your original Form ABT, so you aren’t bound to what you first wrote.⁵

The same 60-day window applies to a deemed denial under the six-month rule. Once you file the petition with the Appellate Tax Board clerk, serve a copy on DOR and confirm service within 10 days.

1
Massachusetts Department of Revenue. Form ABT Application for Abatement
2
Massachusetts Society of CPAs. Form CA-6 Discontinued
3
Massachusetts Department of Revenue. TIR 16-11 Consent to Extend the Time to Act on an Amended Return Treated as an Abatement Application
4
General Court of Massachusetts. Massachusetts General Laws Chapter 62C, Section 37
5
Massachusetts Department of Revenue. AP 627 Applications for Abatement
6
Massachusetts Department of Revenue. File an Appeal or Abatement with MA DOR FAQs
7
Massachusetts Department of Revenue. Power of Attorney POA and Third-Party Authorization
8
Secretary of the Commonwealth of Massachusetts. Property Tax Abatement Tips