Key figures
Oklahoma accounting
2026, with sources
A flat 4% and no franchise tax
Oklahoma taxes corporate income at a flat 4% on Form 512. The return is due 30 days after the federal due date — May 15 for a calendar-year company — and estimated payments are required once the year’s Oklahoma tax is expected to reach $500.
The franchise tax, $1.25 per $1,000 of capital used in Oklahoma, is gone: tax year 2023 was the last year a return was required. Foreign corporations still pay a separate $100 annual registered agent fee to the Tax Commission, which used to ride on the franchise tax return and now has its own form.
Three-factor apportionment
Oklahoma still apportions business income using the arithmetic average of three factors — property, payroll and sales. That makes the location of the team matter for corporate tax, not just for payroll.
Take a 12-person SaaS company with all its people and equipment in Tulsa and 5% of its sales to Oklahoma customers. Its Oklahoma share is roughly (100% + 100% + 5%) ÷ 3, about 68% of apportionable income, taxed at 4%. A company headquartered elsewhere with a few Oklahoma customers apportions very little.
Oklahoma-specific book-tax items
Oklahoma lets taxpayers elect 100% Oklahoma bonus depreciation on qualified property under 68 O.S. §2358.6a: add back federal depreciation in full, subtract Oklahoma bonus depreciation in full, and keep tracking the add-back over the federal recovery period. Oklahoma NOLs are computed independently with reference to IRC §172. Both create Oklahoma-only timing differences in the state provision.
Deadlines
- 30 days after the federal due date (May 15 for calendar years)Oklahoma corporation income tax returnForm 512
- QuarterlyEstimated tax, if the year’s tax is expected to be $500 or moreOW-8-ESC
The federal baseline
This page covers what Oklahoma adds. The federal rules underneath it apply here too.
Common questions
Is Oklahoma’s franchise tax gone?
Yes. Oklahoma’s capital-based franchise tax ended after tax year 2023; there has been no franchise tax filing requirement since tax year 2024. What remains for a Delaware corporation is a $100 annual registered agent fee paid to the Tax Commission on Form FRX-200-R.
When is the Oklahoma corporate return due?
Thirty days after the federal due date — May 15 for a calendar-year corporation whose Form 1120 is due April 15. If no Oklahoma tax is owed, an approved federal extension automatically extends the Oklahoma return; otherwise the company files Form 504-C and pays at least 90% by the original date to avoid the late-payment penalty.
Accounting next door
- KSKansas accountingKansas taxes corporations at 3.5% plus a 3% surtax above $50,000, and apportions by three factors until single sales factor arrives in 2027.
- MOMissouri accountingMissouri taxes corporations at a flat 4% on income apportioned by a single sales factor, with services sourced to the customer. There is no franchise tax.
- 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.
- TXTexas accountingTexas has no corporate income tax. It taxes a company’s margin through the franchise tax, at 0.75%, and nothing is due below $2,650,000 of revenue for 2026 and 2027 reports.
- NMNew Mexico accountingA flat 5.9% corporate income tax from 2025, a $50 franchise tax per corporation, worldwide combined reporting by default and a three-factor apportionment formula.
- COColorado accountingA flat 4.4% corporate income tax on federal taxable income, apportioned on sales. Conformity is rolling, with a 2026 decoupling from the federal FDDEI deduction.
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.
- 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.
- FundraisingAudit-ready books before your Series AInvestors, lenders and auditors ask for the same things: accrual statements, reconciled accounts and support for every balance. How to be ready first.
More of the Oklahoma guide
- ReceivablesReceivables and sales tax in OklahomaSales tax registration, economic nexus, whether SaaS is taxable, and collecting from customers
- PayablesPayables and contractors in OklahomaPaying vendors and contractors: 1099 filing, use tax, contractor tests and withholding
- PayrollPayroll taxes and employer rules in OklahomaWithholding, unemployment insurance, paid leave, minimum wage and the rules on paydays
- ComplianceCompliance and filings in OklahomaRegistering to do business, annual reports, franchise tax and the filing calendar
- AdvisoryAdvisory: credits and decisions in OklahomaCredits, 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.