Key figures
Mississippi accounting
2026, with sources
Income tax with a $5,000 zero bracket
Mississippi taxes corporate income in brackets: nothing on the first $5,000 of taxable income, 4% on the next $5,000 and 5% above $10,000. The corporate return is due on the 15th day of the fourth month after the tax year ends, and an extension requested by that date extends the time to file but not to pay. Corporations with annual income tax liability over $200 make estimated payments.
Mississippi also allows related corporations to file a combined income return, with its own filing and payment procedures published by the Department of Revenue.
A franchise tax in its last years
The franchise tax on capital employed in Mississippi, $0.50 per $1,000 in 2026 with a $25 minimum, is in the final stage of a phase-out that began in 2018. For a startup with $2 million of capital apportioned 10% to Mississippi, the 2026 franchise tax is $100.
Throwback
Mississippi’s sales factor includes a throwback rule. If a Mississippi company sells into a state where it is not required to file an income tax return, those sales are thrown back into the Mississippi numerator. For a SaaS company with a team in Jackson and customers in many states where it has not established a filing obligation, that can push a large share of income into Mississippi until it files elsewhere.
Deadlines
- 15th day of the 4th month after year endCorporate income and franchise tax return (C-corporation)
- Quarterly through the tax yearEstimated income tax, when annual liability exceeds $200
The federal baseline
This page covers what Mississippi adds. The federal rules underneath it apply here too.
Common questions
What is happening to the Mississippi franchise tax?
It is going away. The rate was $0.75 per $1,000 of capital employed for tax years beginning in 2025 and is $0.50 for 2026, with a $25 minimum, as the last steps of a phase-out enacted in 2016. Until then it is reported on the same return as the income tax.
Why might Mississippi tax more of our income than we expect?
Mississippi keeps a throwback rule: sales into a state where the corporation is not required to file an income tax return are added to the Mississippi sales factor numerator. A Mississippi-based startup selling to customers in states where it has no filing obligation can apportion more income here than its customer map suggests.
Accounting next door
- ALAlabama accountingAlabama taxes corporations at 6.5% with a deduction for federal income tax, apportions on a single sales factor, and conforms to federal changes automatically, so it follows federal R&D expensing and bonus depreciation.
- ARArkansas accountingArkansas taxes corporate income on a graduated scale topping out at 4.3%, apportions by a single sales factor with market sourcing under Act 719, and allows no bonus depreciation.
- LALouisiana accountingLouisiana taxes corporate income at a flat 5.5% from 2025 and repealed its capital-based franchise tax for periods from 2026. The CIFT-620 is due May 15 for calendar-year companies.
- TNTennessee accountingTennessee taxes corporations through a 6.5% excise tax on earnings and a 0.25% franchise tax on net worth, apportioned on a single sales factor from 2025, with the property measure repealed in 2024.
Founder guides on this
- US GAAPUS GAAP for early-stage startups, in plain EnglishAccrual accounting, revenue recognition (ASC 606), leases (ASC 842), stock compensation and capitalized software: what each means for a small company.
- The closeWhy startups should close their books every monthA monthly close turns a bank balance into numbers an investor, an auditor or a 409A firm will accept. What it is, and why it gets expensive to skip.
- R&D taxThe R&D tax credit and Section 174A for startupsEngineering salaries can earn a federal R&D credit against payroll tax, and Section 174A lets you deduct US research again. What qualifies, what to track.
More of the Mississippi guide
- ReceivablesReceivables and sales tax in MississippiSales tax registration, economic nexus, whether SaaS is taxable, and collecting from customers
- PayablesPayables and contractors in MississippiPaying vendors and contractors: 1099 filing, use tax, contractor tests and withholding
- PayrollPayroll taxes and employer rules in MississippiWithholding, unemployment insurance, paid leave, minimum wage and the rules on paydays
- ComplianceCompliance and filings in MississippiRegistering to do business, annual reports, franchise tax and the filing calendar
- AdvisoryAdvisory: credits and decisions in MississippiCredits, incentives and the decisions that are cheaper to get right the first time
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.