Ohio Commercial Activity Tax (Ohio CAT Tax) – Complete Guide For LLCs (Mar. 2026)

Your Ohio Limited Liability Company (LLC) is officially established once the state approves your Articles of Organization formation documents. Once approved, you must complete your state tax registration and other mandatory requirements before beginning full business operations.

One important tax to learn about in the state is the Commercial Activity Tax (CAT), also known as the Ohio CAT Tax. All businesses operating in the state that meet the Taxable Gross Receipts (TGR) threshold must register. This requirement also applies to foreign LLCs having a significant nexus in the state.

In this guide, I will walk you through the required steps needed to register for the Ohio CAT Tax. You’ll also learn when you need to file, the associated costs, and what happens if you don’t register.

An Overview Of The Ohio CAT Tax

The Ohio CAT Tax is a privilege tax that applies to Ohio businesses performing any activities for gain, profit, or income at any point during a calendar year. These businesses must register and remit the CAT tax in Ohio to avoid fines and maintain good standing. This is set under O.R.C. § 5751.02.

You must register for the Ohio CAT Tax within 30 days of exceeding the TGR threshold. Otherwise, you do NOT need to register. This is because you must file your tax returns even if you don’t meet the TGR amount if you have an active CAT account.

The table below provides a brief overview of the situations when the Ohio CAT applies to your business. Use this as a handy reference point before learning about the requirements in detail below.

Complete your registration online via the Ohio Business Gateway (OBG). Once completed, you will get your CAT Account Number and Registration Confirmation Number immediately. However, you need to wait around 1-2 days for your account to be ready so you can file CAT returns.

Once registered, any business with an active CAT account must file quarterly returns. The Ohio CAT is taxed at 0.26% on Ohio TGR exceeding the annual exclusion. Therefore, only receipts above the exclusion are taxable. I will discuss this in detail below.

How To Register For The CAT In Ohio

To begin, you need to register for an Ohio Digital Identity (OHID) account on the OBG. This must be done before registering for the CAT. This ID is used across several state business platforms for various filings and tax obligations, including Sales Tax.

If you need further guidance on how to correctly register for your Ohio Sales Tax, read my guide on the Ohio Vendor’s License.

Your OHID is your state tax ID, but your CAT Account Number is issued separately.

I will provide step-by-step instructions on how to create your ID and register for CAT in the following sections.

1. Create Your OHID

First, access the OBG page. Then, click “Login” on the main page.

Next, click “Create account” to begin your account creation process.

a. Complete The Email Verification Process

Step 1 requires you to verify your email address. Enter your email twice in the applicable fields. Then, click “Send PIN” to receive an email with your verification PIN.

Next, enter your email PIN code and click “Next.”

b. Input Your Personal Information

Step 2 asks you to provide your personal information. Enter your legal first name, last name, and date of birth in the fields provided. Then, click “Submit” once you’ve completed the required fields.

c. Choose A Suitable Username

After completing your personal information, you must enter your desired username into the system.

Ensure you follow these rules:

• Your username must have 6-64 characters.
• It can NOT start or end with a special character.
• It can NOT contain only numbers.
• It can NOT contain special characters (except periods (.), dashes (-), underscores (_), or at signs (@).

Example: johndoe@1234 is an excellent example of a username that would be accepted.

d. Create Your Password

After choosing your username, the system will ask you to create your OHID password.

Again, follow these rules to ensure it’s accepted by the system:

• It must contain at least 12 characters.
• It must have an uppercase letter, a lowercase letter, and a number.
• It must have a special character.

Example: Password@12345678! is a great example of a strong password.

e. Provide A Recovery Phone Number

With your username and password set, you must next enter your business phone number. Once entered, click “Send PIN.”

Use the PIN provided to verify your phone number and click “Next.”

f. Agree To The Terms & Conditions

Check “I agree” under the terms and conditions box to agree to them. These explain your responsibilities and obligations when creating your account. I advise reading them carefully so you understand what you’re agreeing to.

Click “Create account” once you’re ready to move to the next step.

2. Set Up Your Business Details

With your OHID account set up, your next step is to set up your business details. This must be done BEFORE registering for your CAT.

a. Login To The Business Gateway

Go back to the OBG’s main page. Then, click “Login.”

Provide your username and password to log in to your account.

After logging in to your account, enter the verification PIN sent to your email address.

b. Enter Your Employer Identification Number (EIN)

Next, enter your business’s EIN. Click “Next” once everything is complete.

Choose “EIN” if your account wasn’t found on the system. Then, click “Next” to continue to the next stage of your filing.

c. Provide Your Business’s Initial Information

In the next stage, you’ll be asked about the nature of your account. State your business’s legal name, address, and phone number as required. Then, click “Next” once the required fields are complete.

3. Add The CAT To Your Service List

a. Redirection To The Business Gateway Dashboard

After setting up your business details, the system will take you back to the main “My Business | Dashboard” page. Click the “Lock icon” to start registering for CAT.

b. Choose The CAT Service

Next, you’ll be taken to the “Account access management” page. Click the plus icon next to “Commercial Activity Tax”.

The system should then transfer the service to the right side in the “Authorized service areas” section. This means that you’ve successfully chosen this service for your business.

c. Authorize The Service

In this section, authorize the service so the system can access your OHID information. This includes your business information, such as your name, EIN, etc.

Click on the “User authorization” tab. Then, turn on all the buttons in the “Permission template” box. Finally, choose “Copy permissions” and click “Save”.

4. Start Registering For The CAT

Once registered, your main dashboard will show the CAT service. Click the “Play” icon and follow the system prompts to start registering. This requires you to answer several questions regarding your business.

You can read the Ohio CAT Tax Instructions for Registration resource for the list of questions that you may be asked when filing.

a. Gather Information About Business Activity And Structure

First, determine your CAT filing profile based on your LLC’s business activity and structure.

Provide the following information:

• Type of organization: Choose between Sole Proprietorship, Corporation, Partnership, or LLC.
• Date: When your LLC exceeded or is expected to exceed the CAT TGR threshold.
• Estimated annual Ohio TGR: This is for the current year.
• Type of taxpayer: This may be a single entity, a combined taxpayer, or a consolidated elected taxpayer.

b. Gather Other Information

After entering information about your business activity and structure, you must prepare additional general business and registration details.

This includes your:

• Ohio Secretary of State charter, registration, or license number (if registered in Ohio).
• Your six-digit NAICS code describing your primary business activity.

c. Gather Member’s Information

Choosing your type of organization and taxpayer classification means that you’re also determining how your owner or member information will be reported.

• You may need to enter information regarding your corporate officers, partners, or members of the primary entity if you select anything other than a sole proprietorship.
• You may need to list all entities included in the group if you register as a combined taxpayer or a consolidated elected taxpayer.
• For consolidated elected taxpayers, the entities listed are bound by the consolidation election.

Who Needs To File For The CAT

1. Filing Threshold Requirements

Businesses with more than $3 million in annual Ohio TGR were required to pay CAT in 2024. However, the threshold changed to $6 million in 2025.

a. In-State Business

As I’ve stated above, all in-state businesses with more than $6 million in Ohio TGR in a year must register for CAT. This needs to be done within 30 days after exceeding the threshold.

b. Out-Of-State Business

Foreign businesses are required to pay CAT if they have more than $6 million in Ohio TGR and a substantial nexus with Ohio. They must also register for a CAT account within 30 days of exceeding the threshold.

A business creates a substantial nexus if it has a bright-line presence in the state. This means that any of the following apply during the year:

1. The business owns property in Ohio worth $50,000 or more.
2. The business pays $50,000 or more in wages to people working in Ohio.
3. The business makes $500,000 or more in sales to Ohio customers.
4. 25% or more of the business’s total property, payroll, or sales is in Ohio.
5. The business is domiciled (based or headquartered) in Ohio.

2. Exemptions

These types of business are excluded from the CAT according to the Department of Taxation’s guide:

• Some public utilities (Like telegraph, natural gas, pipeline, water, and heating companies).
• Small businesses with low sales (Businesses with $6 million or less in taxable sales are excluded).
• Insurance companies that pay the insurance premiums tax.
• Dealers in intangibles who already pay a special Ohio tax.
• Non-profit groups.

Due Dates For Your CAT Filing

All businesses with an active Ohio CAT account must file quarterly returns after registering.

This is the quarterly filing schedule:

How Much Is The CAT?

You should primarily consider the tax rate and applicable exclusion when determining how much CAT you need to pay.

As I’ve briefly mentioned above, the Ohio CAT is taxed at 0.26% (0.0026) of Ohio TGR above the annual exclusion amount ($6 million).

Example: Your Ohio TGR is $7 million.

• The state’s threshold is $6 million.
• Only $1 million is actually taxable.
• Your CAT due is 0.26% of $1 million ($2,600).

The annual exclusion uses a year-to-date (Cumulative) approach. Therefore, while the $6 million exclusion applies once per year and does NOT reset each quarter, any unused portion automatically carries forward to later quarters in the same year.

I’ve provided another example below for you to better understand how tax is calculated throughout the year:

• Q1: Your LLC has $1,000,000 in TGR, meaning $1,000,000 of the $6,000,000 exclusion is used. In this case, no CAT is due, and you’re not required to register.
• Q2: Your LLC has an additional $2,000,000 in receipts. Your new year-to-date total is $3,000,000, meaning that you have $3,000,000 of the exclusion left. Therefore, no CAT is due, and NO registration is needed.
• Q3: Your LLC has an additional $3,500,000 in receipts. Your year-to-date total reaches $6,500,000, exceeding the $6,000,000 annual exclusion. Therefore, you must register for the CAT within 30 days. However, the CAT only applies to the amount over the threshold ($6,500,000 – $6,000,000 = $500,000). Your CAT due is 0.26% × $500,000 = $1,300.
• Q4: Your LLC has an additional $1,000,000 in receipts. Your exclusion has already been fully used. Therefore, the entire $1,000,000 is taxable. Your CAT due for Q4 is 0.26% × $1,000,000 = $2,600.

Your exclusion resets to $6 million the following year, meaning the entire process starts again from the beginning.

Estimated Returns

Ohio businesses can file estimated quarterly returns if their actual Ohio TGR are NOT available by the due date. This protects your LLC in unexpected situations.

You have two types of estimated returns to be aware of. I’ve summarized them in the table below:

Here are some examples of how you should calculate your estimated return:

1. Rule-Based Estimated Return

a. 95% Of Last Quarter’s TGR Method

Your business had $7,000,000 of Ohio TGR in Q1. Your $6,000,000 annual exclusion was fully used, so $1,000,000 was subject to CAT in Q1. Therefore, your TGR in future quarters is fully taxable.

You don’t have your final Q2 numbers ready by the filing deadline. As a result, you choose the rule-based estimated return using the 95% of the last quarter TGR method.

In this case:

• You estimate Q2 TGR using 95% of Q1 taxable receipts. This is 95% × $7,000,000 = $6,650,000.
• Your CAT due according to the estimate is: 0.26% × $6,650,000 = $17,290.

Following this, your actual Q2 receipts become available:

• If your Q2 TGR turns out to be $7,000,000, your actual CAT due is 0.26% × $7,000,000 = $18,200. Since you’ve already paid $17,290 with your estimated return, your additional amount due with the reconciliation return is $18,200 – $17,290 = $910.
• If your Q2 TGR is $6,000,000, your actual CAT due is 0.26% × $6,000,000 = $15,600. You’ve already paid $17,290 with your estimated return, so you overpaid: $17,290 – $15,600 = $1,690. In this case, you can request a refund for the overpaid amount.

b. 70% Of The Actual Tax Method

Using the same example above, you instead chose the rule-based estimated return using the 70% payment method:

• First, you estimate your Q2 TGR to be $7,000,000.
• Based on your estimate, your estimated CAT due for Q2 is: 0.26% × $7,000,000 = $18,200.
• Under the 70% rule, you must pay at least 70% of your estimated CAT due. This is:
  70% × $18,200 = $12,740.

When filing your true-up (reconciliation) return, your actual Q2 TGR is determined. If your actual Q2 TGR is $7,500,000, your actual CAT due is: 0.26% × $7,500,000 = $19,500.

As you’ve already paid $12,740, you need to pay the remaining $6,760 with your reconciliation return.

2. Statutory Estimated Return

Let’s assume that your LLC had $6,500,000 of Ohio TGR in Q1. Because your $6,000,000 annual exclusion was fully used in Q1, $500,000 was subject to CAT. Therefore, all TGR from Q2 forward is fully taxable.

With no final Q2 numbers available, you choose to file a statutory estimated return for Q2.

• You estimate your Q2 Ohio TGR at $3,000,000.
• The entire $3,000,000 is taxable because your exclusion has already been used.
• You file your Q2 statutory estimated return and pay a CAT of 0.26% × $3,000,000 = $7,800.

Once your actual Q2 results are finalized, your TGR turns out to be $3,100,000. Your $3,000,000 estimate equals 96.77% of your actual TGR, which falls within the statutory 95% – 105% safe harbor. Therefore, no penalty applies.

You file using your actual number for the rest of the year. This is Q3 TGR $4,000,000 and Q4 TGR $3,200,000.

Ohio requires a full-year reconciliation at the end of the year, even though you only estimated for Q2. Assuming your total Ohio TGR for the year is:

• Q1: $6,500,000.
• Q2: $3,100,000.
• Q3: $4,000,000.
• Q4: $3,200,000.

Your total annual Ohio TGR: $16,800,000.

After you’ve applied the $6,000,000 annual exclusion, your taxable TGR for the year is: $16,800,000 – $6,000,000 = $10,800,000.

Your actual CAT due for the year is: 0.26% × $10,800,000 = $28,080.

This is your CAT paid during the year based on your quarterly filings:

• Q1: 0.26% × $500,000 = $1,300.
• Q2 (estimated): $7,800.
• Q3: 0.26% × $4,000,000 = $10,400.
• Q4: 0.26% × $3,200,000 = $8,320.

Total CAT paid: $27,820.

Therefore, with the year-end reconciliation return, you need to pay the remaining: $28,080 – $27,820 = $260.

Canceling Your CAT Account

You must complete your ongoing filings to maintain an active CAT account, even if no tax is due. The state allows you to cancel your account if your LLC no longer meets the CAT threshold. This reduces your filing burden and means that you can reactivate it later if needed:

• Navigate to the OBG and choose “CAT cancel account.” Check the cancellation box when filing your final tax return.
• Complete the Business Account Update Form to request the cancellation if you can’t cancel your account using the method above.

Why Do You Need To Register To Pay And File The Ohio CAT?

Your LLC faces delinquency notices and penalties if you fail to file and pay the required Ohio CAT.

1. Interest

If your CAT is NOT paid on time, interest is charged from the due date until your tax is paid or assessed under O.R.C. § 5751.06(F).

Under O.R.C. § 5730.47, the state sets yearly interest rates based on the federal short-term rate, then adds 3%. This rate is set every October and applies to tax interest for the following year.

By Oct. 15 of each year, the Ohio Tax Commissioner certifies the interest rates that apply to overdue taxes during the next calendar year. Check for the updates in the Official Interest Rates page.

2. Monetary Penalties

The state may impose a penalty of up to 10% of the additional tax due if a taxpayer incorrectly reports TGR under O.R.C. § 5751.06(G). The Department of Taxation further states that the penalty is the greater of 10% of the tax due or $50.

Failure to register on time may result in a penalty of up to $100 per month, not exceeding $1,000.

Department Of Taxation Key Contact Information

Contact the Ohio Department of Taxation if you have any issues completing your application or understanding the requirements.

I’ve provided their main contact details below:

Online: Log in to OH Tax e-Services, navigate to “Additional resources,” and click “Send a message.”

Visitor center walk-ins/Scheduled appointments: Google Map.

General Business Inquiries
Phone: (888) 405-4039
Ohio Department of Taxation
Attn: Business Tax Division
P.O. Box 2678
Columbus, OH 43216-2678

Business Registration
Phone: (888) 405-4089

Frequently Asked Questions