Ohio Business Tax — CAT, LLC, S-Corp Guide

Ohio Business Tax — CAT, LLC, S-Corp Guide

Ohio Tax Overview

Ohio's business tax landscape is unique, primarily characterized by the Commercial Activity Tax (CAT), which serves as a gross receipts tax rather than a traditional corporate income tax. This distinction is crucial for practitioners advising businesses operating within or considering entry into the Ohio market. Understanding the nuances of the CAT, along with other state-specific requirements such as LLC biennial reports and S-Corporation treatment, is paramount for effective tax planning and compliance in 2026.

Key Ohio Tax Rules for Business Owners (2026)

• Individual Income Tax: Ohio imposes a state income tax. For 2026, the state is transitioning to a flatter tax structure, with a rate of 2.75% on income above a certain threshold [7]. This change streamlines tax calculations for individuals, including business owners who report pass-through income.

• Commercial Activity Tax (CAT): The CAT is levied on the privilege of doing business in Ohio. For 2026, the tax rate remains 0.26% (0.0026) on taxable gross receipts exceeding the annual exclusion amount [1, 3]. Significant changes have been implemented regarding the exclusion threshold:

  • Prior to 2024: Businesses with more than $150,000 in Ohio Taxable Gross Receipts (TGR) were subject to CAT.
  • For 2024: The exclusion increased to $3 million in Ohio TGR.
  • For 2025 and forward (including 2026): Businesses with $6 million or less in Ohio TGR are exempt from the CAT [1, 3, 4]. This significantly reduces the CAT burden for many small and medium-sized businesses.

• LLC Fees: Ohio requires a $99 biennial report fee for Limited Liability Companies (LLCs) [1]. This fee is a standard administrative requirement for maintaining good standing with the state.

• S-Corp Rules: Ohio does not impose a traditional corporate income tax. Consequently, both S-Corporations and C-Corporations are subject to the CAT on their gross receipts, provided they exceed the applicable exclusion threshold [1]. Ohio generally conforms to federal S-Corp elections for income tax purposes, but the CAT applies irrespective of federal entity classification.

Detailed Implementation Guide: Navigating Ohio Business Taxes

Practitioners must guide their clients through the complexities of Ohio's business tax system, particularly concerning the CAT. This guide provides step-by-step instructions for ensuring compliance and optimizing tax positions.

Step 1: Determine CAT Applicability and Nexus

Before any other steps, assess whether a business has nexus with Ohio and if its gross receipts exceed the CAT exclusion threshold for 2026.

1. Establish Ohio Nexus: A business has Ohio nexus if it meets any of the following criteria during the calendar year (known as "bright-line presence") [1]:

   • Property in Ohio with a value of $50,000 or more.
   • Payroll in Ohio of $50,000 or more.
   • Sales in Ohio of $500,000 or more.
   • 25% or more of total property, payroll, or sales are in Ohio.
   • Domiciled (based or headquartered) in Ohio.

   Practitioner Note: Even if a business meets one of these nexus criteria, it only owes CAT if its Ohio sales exceed the exclusion amount. For 2026, this threshold is $6 million [1].

2. Calculate Taxable Gross Receipts (TGR): Determine the total gross receipts from business activities in Ohio. This includes all receipts from sales of property, services, and rentals within the state. Certain receipts may be excluded, such as those from sales to other businesses that are also subject to CAT, or receipts from certain financial transactions [1].

3. Apply Exclusion Threshold: For 2026, if the business's Ohio TGR is $6 million or less, it is not subject to the CAT. If TGR exceeds $6 million, the business is subject to CAT on the amount exceeding this threshold [1, 3].

Step 2: CAT Registration and Account Management

If a business is subject to CAT, timely registration and proper account management are critical.

1. Register with the Ohio Department of Taxation (ODT): Businesses must register for CAT within 30 days of exceeding the Ohio TGR minimum threshold. Registration can be completed through the Ohio Business Gateway [1]. Failure to register timely can result in penalties of up to $100 per month, not to exceed $1,000 [1].

2. Determine Filing Frequency: All taxpayers subject to CAT must file quarterly returns [12]. Annual filings were eliminated after the 2023 tax year. The ODT will typically notify registered businesses of their filing frequency.

3. Account Cancellation/Reactivation: If a business's TGR falls below the $6 million exclusion threshold, practitioners should advise clients on whether to cancel their CAT account or continue filing. Continuing to file may be advisable if future TGR is expected to exceed the threshold again, as it avoids the need for re-registration. If an account is canceled, re-registration is required within 30 days of exceeding the threshold again [1].

Step 3: Calculating and Paying CAT

Accurate calculation and timely payment are essential for CAT compliance.

1. Calculate Taxable Gross Receipts (TGR) for the Period: For each quarterly filing period, determine the TGR generated in Ohio. Remember to subtract any excluded receipts.

2. Apply the Exclusion: Subtract the applicable exclusion amount from the TGR. For quarterly filers, the annual $6 million exclusion is typically prorated across the quarters. However, the ODT guidance indicates that the tax is applied to receipts exceeding the annual exclusion, implying a cumulative application rather than a strict quarterly proration of the exclusion itself [1]. Practitioners should consult the latest ODT guidance for precise application.

3. Calculate CAT Liability: Multiply the taxable gross receipts (after exclusion) by the CAT rate of 0.26% (0.0026) [1, 3].

4. Timely Filing and Payment: Quarterly CAT returns and payments are due on the 10th day of the second month following the end of the calendar quarter (e.g., May 10 for Q1, August 10 for Q2, November 10 for Q3, and February 10 for Q4) [5, 12].

Step 4: Understanding Credits and Exemptions

While the CAT is a broad-based tax, certain exemptions and credits may apply.

1. Excluded Entities: Certain entities are exempt from CAT, including non-profit organizations, most government agencies, some public utilities, dealers in intangibles, financial institutions, and insurance companies [1].

2. Sales-Based Exclusions: As noted, businesses with $6 million or less in Ohio TGR for 2025 and beyond are excluded from CAT [1, 3, 4].

3. Credits: Ohio offers various tax credits that may offset other state tax liabilities, though direct CAT credits are less common. Practitioners should research available credits through the ODT website or relevant tax publications to identify any applicable to their clients [11].

Step 5: Record Retention

Maintain meticulous records to support all CAT calculations and filings. Under most circumstances, records must be kept for four years from the date the tax is due or filed, whichever is later [1].

Real Numbers Example: Ohio Commercial Activity Tax (CAT) Calculation (2026)

Let's consider a hypothetical Ohio-based manufacturing company, "Buckeye Innovations LLC," for the 2026 tax year.

Scenario:

Buckeye Innovations LLC has the following gross receipts for 2026:

• Total Gross Receipts from all operations: $10,000,000
• Gross Receipts from sales to Ohio customers: $8,500,000
• Gross Receipts from sales to out-of-state customers: $1,500,000
• Excluded receipts (e.g., sales to other CAT taxpayers): $500,000

Calculation Steps:

1. Determine Ohio Taxable Gross Receipts (TGR):

   • Ohio Sales: $8,500,000
   • Less: Excluded Receipts: $500,000
   • Net Ohio TGR: $8,000,000

2. Apply the CAT Exclusion Threshold:

   • For 2026, the exclusion threshold is $6,000,000 [1, 3].
   • Net Ohio TGR ($8,000,000) exceeds the exclusion threshold.

3. Calculate Taxable Amount:

   • Net Ohio TGR: $8,000,000
   • Less: Exclusion: $6,000,000
   • Taxable Amount: $2,000,000

4. Calculate CAT Liability:

   • Taxable Amount: $2,000,000
   • CAT Rate: 0.26% (0.0026) [1, 3]
   • Annual CAT Liability: $2,000,000 * 0.0026 = $5,200

Quarterly Payments:

Buckeye Innovations LLC would owe $5,200 in CAT for 2026. This amount would typically be paid in four equal quarterly installments of $1,300 each, due on the 10th day of the second month following the end of each calendar quarter [5, 12].

State Applicability and State-Specific Considerations

Ohio's tax structure, particularly the CAT, presents unique considerations for businesses and practitioners, especially when compared to states with traditional corporate income taxes.

Ohio's Approach vs. Traditional Corporate Income Tax

Unlike many states that levy a corporate income tax on net profits, Ohio's CAT is a gross receipts tax. This means it is imposed on a business's total revenue before deductions for expenses. This fundamental difference has several implications:

• Profitability Irrelevant: A business can be unprofitable but still owe CAT if its gross receipts exceed the exclusion threshold. This can be a significant burden for startups or businesses experiencing temporary losses [1].

• No Income Apportionment: While gross receipts are sourced to Ohio, the CAT does not involve complex income apportionment formulas based on property, payroll, and sales factors typically used for corporate income taxes. Instead, it focuses on the situs of the gross receipts [1].

• Impact on Different Industries: Businesses with high gross receipts but low-profit margins (e.g., distributors, retailers) may find the CAT disproportionately burdensome compared to businesses with lower gross receipts but higher profit margins (e.g., service providers) [1].

S-Corporations and LLCs in Ohio

Ohio's treatment of S-Corporations and LLCs under the CAT is another key state-specific consideration.

• S-Corporations: Federally, S-Corporations pass their income, losses, deductions, and credits through to their shareholders for federal income tax purposes, avoiding corporate-level income tax. Ohio conforms to this federal treatment for individual income tax purposes. However, for the CAT, S-Corporations are treated like any other business entity and are subject to the CAT on their Ohio TGR if they exceed the exclusion threshold [1]. This means an S-Corp in Ohio may still have a corporate-level tax liability through the CAT, which is not the case in states with only corporate income taxes.

• Limited Liability Companies (LLCs): LLCs offer flexibility in federal tax classification (e.g., disregarded entity, partnership, S-Corp, C-Corp). Regardless of federal classification, an LLC conducting business in Ohio and exceeding the CAT exclusion threshold will be subject to the CAT. Additionally, all LLCs must pay the $99 biennial report fee to the Ohio Secretary of State [1].

Conformity to Federal Tax Provisions

Ohio generally conforms to many federal tax provisions, but practitioners must be aware of specific differences or nuances.

• Bonus Depreciation: Ohio generally follows federal bonus depreciation rules, which allow businesses to immediately deduct a large percentage of the cost of eligible property. For 2026, federal bonus depreciation is 60% [8]. While Ohio conforms to the federal deduction, state-specific adjustments or limitations may apply in certain contexts, particularly for the calculation of state income tax for individuals or pass-through entities.

• Qualified Business Income (QBI) Deduction: The federal QBI deduction (IRC Section 199A) allows eligible pass-through entities to deduct up to 23% of qualified business income (OBBBA §70301 increased from 20%). For 2026, the QBI deduction is 23% under the Build Back Better Act (OBBBA) [9]. Ohio generally conforms to the federal adjusted gross income (AGI) for individual income tax purposes, which would indirectly reflect the QBI deduction. However, the QBI deduction does not directly impact the CAT, as CAT is based on gross receipts.

• State and Local Tax (SALT) Deduction Limitation: The federal SALT deduction is capped at $10,000 for individuals. Ohio has implemented a workaround for pass-through entities, allowing them to pay state and local taxes at the entity level, which can bypass the federal SALT cap for individual owners. Practitioners should advise clients on the benefits and mechanics of the Ohio Pass-Through Entity Tax (PTE Tax) election [6].

Common Mistakes and Audit Triggers in Ohio Business Taxation

Practitioners should be vigilant in helping clients avoid common pitfalls that can lead to non-compliance, penalties, and audits by the Ohio Department of Taxation.

1. Misinterpreting CAT Nexus and Exclusion Thresholds

• Mistake: Assuming no CAT liability because the business is not physically located in Ohio, or miscalculating the $6 million exclusion threshold for 2026.

• Audit Trigger: Significant Ohio-sourced gross receipts without CAT registration or filing, or inconsistent application of the exclusion threshold across periods.

• Best Practice: Thoroughly review the "bright-line presence" rules for nexus and accurately track Ohio TGR to ensure correct application of the $6 million exclusion. Document all nexus determinations and TGR calculations [1].

2. Incorrectly Sourcing Gross Receipts

• Mistake: Improperly classifying receipts as Ohio-sourced or out-of-state, leading to underreporting or overreporting of Ohio TGR.

• Audit Trigger: Discrepancies between reported Ohio sales for CAT purposes and sales reported for other state tax purposes or financial statements. Complex sales arrangements without clear sourcing documentation.

• Best Practice: Establish clear policies and procedures for sourcing gross receipts based on ODT guidance, particularly for sales of tangible personal property and services. Maintain detailed records supporting all sourcing decisions [1, 10].

3. Failure to Register or File Timely

• Mistake: Delaying CAT registration after exceeding the threshold or missing quarterly filing deadlines.

• Audit Trigger: Late registration or consistent late filings, which can trigger automated penalty assessments and draw ODT attention.

• Best Practice: Implement a robust compliance calendar to track CAT registration deadlines and quarterly filing due dates. Register promptly once the TGR threshold is met [1].

4. Misunderstanding the Nature of CAT (Gross Receipts vs. Income Tax)

• Mistake: Treating CAT as an income tax and attempting to deduct expenses, or assuming S-Corporations are exempt from CAT due to their federal pass-through status.

• Audit Trigger: Deducting expenses from gross receipts on CAT returns, or S-Corporations failing to file CAT returns when required.

• Best Practice: Educate clients on the fundamental difference between a gross receipts tax and an income tax. Emphasize that CAT is levied on gross receipts before expenses and applies to most business entities, including S-Corporations, if they meet the TGR threshold [1].

5. Inadequate Record Keeping

• Mistake: Failing to retain sufficient documentation to support reported gross receipts, exclusions, and nexus determinations.

• Audit Trigger: Inability to provide requested documentation during an ODT audit, leading to potential assessments and penalties.

• Best Practice: Maintain comprehensive records for at least four years, including sales invoices, contracts, financial statements, and any internal documentation related to CAT calculations and nexus determinations [1].

Client Conversation Script: Explaining Ohio Business Taxes

This script provides a framework for practitioners to discuss Ohio business taxes, particularly the CAT, with clients in a clear and concise manner.

Practitioner: "Good morning/afternoon, [Client Name]. Thanks for meeting with me today to discuss your Ohio business tax obligations for 2026. I know state taxes can be complex, especially with Ohio's unique system."

Client: "Thanks. I've heard about this CAT tax, but I'm not entirely clear on how it works or if it even applies to my business."

Practitioner: "That's a common concern. Let's break it down. Ohio doesn't have a traditional corporate income tax like many other states. Instead, it has what's called the Commercial Activity Tax, or CAT. Think of it as a tax on your gross receipts, or total revenue, from doing business in Ohio, before you even consider your expenses."

Client: "So, it's not based on my profit? Even if I'm not making money, I could still owe this tax?"

Practitioner: "Exactly. That's a key difference. The CAT is levied on your taxable gross receipts (TGR) sourced to Ohio. The good news for many smaller businesses is that for 2026, there's a significant exclusion. If your Ohio TGR is $6 million or less, you generally won't owe any CAT [1, 3]."

Client: "$6 million? That's a big jump from what I remember. So, if my Ohio sales are under that, I don't have to worry about it?"

Practitioner: "For the most part, yes. However, we still need to determine if your business has nexus with Ohio. That means, does your business have a sufficient connection to the state? This could be through property, payroll, or sales exceeding certain thresholds, even if you're not physically headquartered there [1]. If you have nexus and your Ohio TGR exceeds $6 million, then you'll be subject to the CAT at a rate of 0.26% on the amount above that exclusion [1, 3]."

Client: "What about my LLC or S-Corp? I thought S-Corps avoided corporate-level taxes."

Practitioner: "That's true for federal income tax purposes, and Ohio generally conforms to federal S-Corp treatment for individual income tax. However, the CAT applies to most business entities, including S-Corporations and LLCs, if they meet the TGR and nexus thresholds. So, an Ohio S-Corp could still have a CAT liability [1]. For LLCs, there's also a $99 biennial report fee to the Ohio Secretary of State [1]."

Client: "Okay, so it's about gross receipts, not profit, and there's a big exclusion now. What do I need to do to stay compliant?"

Practitioner: "First, we'll confirm your Ohio nexus and TGR. If you're subject to CAT, we'll ensure you're properly registered with the Ohio Department of Taxation. Then, we'll track your Ohio gross receipts quarterly and file the necessary returns and payments by the due dates. It's crucial to keep excellent records to support all your figures [1]. We'll also look at any other state-specific considerations, like the Ohio PTE Tax election, which could benefit you [6]."

Client: "That makes a lot more sense. Thanks for clarifying. What are the common mistakes businesses make?"

Practitioner: "The biggest ones are often misinterpreting nexus, incorrectly sourcing receipts, or simply failing to register or file on time. Also, sometimes businesses confuse the CAT with an income tax and try to deduct expenses, which isn't allowed. We'll make sure we avoid all those pitfalls [1]."

Client: "Great. Let's make sure we're on top of this."

Practitioner: "Absolutely. I'll prepare a detailed summary and outline the next steps for your business."

Frequently Asked Questions (FAQs)

Here are answers to common questions regarding Ohio business taxes, updated for 2026.

References

[1] Ohio Department of Taxation. “Commercial Activity Tax (CAT).” tax.ohio.gov. Accessed April 8, 2026. https://tax.ohio.gov/business/commercial-activity-tax
[2] Policy Matters Ohio. “The Great Ohio Tax Shift, 2026.” policymattersohio.org. Accessed April 8, 2026. https://policymattersohio.org/research/the-great-ohio-tax-shift-2026/
[3] CLA Connect. “Ohio Commercial Activity Tax Rules Affect Taxpayers.” claconnect.com. March 17, 2026. https://www.claconnect.com/en/resources/articles/26/ohio-commercial-activity-tax
[4] HBK CPA. “Ohio CAT Exclusion Increases January 1, 2025.” hbkcpa.com. January 1, 2025. https://hbkcpa.com/insights/ohio-cat-exclusion-increases-january-1-2025/
[5] Ohio Department of Taxation. “CAT Reminder for Practitioners & Taxpayers.” facebook.com/OhioDepartmentOfTaxation. February 5, 2026. https://www.facebook.com/OhioDepartmentOfTaxation/posts/-cat-reminder-for-practitioners-taxpayers-the-4th-quarter-2025-commercial-activi/1226164389701458/
[6] Vorys. “Ohio Begins Broader Tax Restructuring with New Budget Bill.” vorys.com. August 12, 2025. https://www.vorys.com/publication-ohio-budget-2026-2027-sales-and-use-tax-update
[7] Darkhorse CPA. “Ohio Moves to a Flat Tax in 2026: What It Means for You.” darkhorse.cpa. Accessed April 8, 2026. https://darkhorse.cpa/what-ohio-s-new-budget-means-for-taxpayers/
[8] Internal Revenue Service. “Publication 946, How To Depreciate Property.” irs.gov. Accessed April 8, 2026. https://www.irs.gov/publications/p946
[9] Internal Revenue Service. “Qualified Business Income Deduction (Section 199A).” irs.gov. Accessed April 8, 2026. https://www.irs.gov/newsroom/qualified-business-income-deduction-section-199a
[10] RSM US LLP. “Ohio addresses CAT impact of goods shipped through the state.” rsmus.com. February 5, 2026. https://rsmus.com/insights/tax-alerts/2026/ohio-addresses-cat.html
[11] Harvest CPA Firm. “5 Tax Credits for Ohio Business Owners to Claim Before 2026.” harvestcpafirm.com. November 17, 2025. https://harvestcpafirm.com/5-tax-credits-for-ohio-business-owners-to-claim-before-2026/
[12] Kirsch CPA Firm. “Is Your Business Subject to CAT Tax?” kirschcpa.com. January 15, 2025. https://kirschcpa.com/accounting-services-blog/is-your-business-subject-to-cat-tax/