Skip to content
Join the waitlist

Accounting and state tax in Maine

Maine taxes corporations at graduated rates from 3.5% to 8.93% on apportioned income, with combined reporting for unitary groups and income-tax nexus at $500,000 of Maine sales.

Jurisdiction
Maine
Reading time
2 min
Checked
October 12, 2026
Point at another state to compare its accounting.

Key figures

Maine accounting

2026, with sources

Corporate tax rates
3.5% to 8.93%Brackets at $350,000, $1,050,000 and $3,500,000.
Income tax nexus
$500,000 of Maine salesOr $250,000 of property or payroll, or 25% of any factor.
Apportionment
Sales factor
Unitary groups
Combined reportingCombined report under MRS Rule 810.
IRC conformity (2025 returns)
Code as of Dec 31, 2024OBBBA conformity left to the 2026 Legislature.
Bonus depreciation
DecoupledAdded back, recovered in later years.

Graduated rates on apportioned income

Maine taxes corporations on federal taxable income, as modified by Maine law and apportioned to Maine, at graduated rates: 3.5% up to $350,000; $12,250 plus 7.93% up to $1,050,000; $67,760 plus 8.33% up to $3,500,000; and $271,845 plus 8.93% above that. There is no minimum tax, and Maine’s franchise tax applies to financial institutions rather than ordinary corporations.

Since 2022, a corporation has Maine income tax nexus once, as apportioned to Maine, it has more than $500,000 of sales, $250,000 of property or $250,000 of payroll, or 25% of any of its total property, payroll or sales. Apportionment uses a sales factor, and members of a unitary business file a combined report.

Conformity in flux

For 2025 returns, Maine conforms to the Internal Revenue Code as of December 31, 2024. The 2025 federal law (P.L. 119-21) was left to the Legislature’s 2026 session, and in the meantime the Governor directed the State Tax Assessor to follow federal treatment for several items, including § 179 expensing, the business interest deduction and research and experimental expenditures (for small business amended returns). MRS said taxpayers could file on extension while waiting for legislation.

For a startup that expensed domestic R&E federally under § 174A, the Maine treatment of that deduction is the line to confirm with the Office of Tax Policy’s current conformity guidance before closing the state provision.

Book-tax differences

Maine adds back federal bonus depreciation and recovers it through later-year subtractions, so a company buying servers or lab equipment carries a Maine depreciation difference for years. Corporations owing $1,000 or more pay estimates in four equal installments, and the automatic extension (federal extension plus 30 days, or seven months) only avoids penalties if 90% of the tax is paid by the original due date.

Deadlines

  1. Apr 15 for calendar yearsCorporate income tax returnForm 1120ME
  2. No form requiredAutomatic extension: federal extension plus 30 days, or 7 months, whichever is later; 90% of tax due by the original date
  3. 15th day of months 4, 6, 9 and 12Estimated tax unless liability is under $1,000Form 1120ES-ME

The federal baseline

This page covers what Maine adds. The federal rules underneath it apply here too.

FederalFederal accounting for startupsFederal law sets the tax rules, not the bookkeeping ones: US GAAP comes from the FASB and from what investors expect, while Form 1120, the cash-method test and Section 174 come from the IRS. Every state builds its corporate tax on this return.

Common questions

When does an out-of-state corporation owe Maine income tax?

Once its Maine-apportioned sales exceed $500,000, or its Maine property or payroll exceeds $250,000, or 25% of its total property, payroll or sales is in Maine, for tax years beginning in 2022 or later. One full-time engineer in Portland on a $150,000 salary doesn’t reach the payroll threshold alone.

Does Maine follow the 2025 federal tax law?

Maine conformed to the Code as of December 31, 2024 for 2025 returns. The Governor directed MRS to follow federal treatment of several 2025 changes, including research and experimental expenditures for small business amended returns, pending legislation; MRS publishes the conformity documents and has told taxpayers they may file on extension until the Legislature acts.

Accounting next door

How Maine compares

Founder guides on this

Works in your QuickBooks Online or Xero file

Want accounting handled?

Lopifi is building AI bookkeeping that keeps your books closed on US GAAP and watches deadlines like these, with a CPA review every quarter, for $200 a month. We’re not open yet.

$200/month when we open. No card now.

More of the Maine guide

Sources

Checked against each agency’s own page on . Rates and thresholds change, usually on January 1.

General information for US companies, not tax, legal or accounting advice for yours. Rules and thresholds change; confirm the specifics with a CPA or the agency before you act on them.

All state guides