Last Updated: June 10, 2024, 9:43 am by TRUiC Team


How to Start an S Corp in Illinois

As you plan to start a business, you’ll have much to consider — from the upfront costs to how you want to structure your business. While it can seem overwhelming at times, starting a business in Illinois is easy. The state offers entrepreneurs affordable tax rates, high business survival rates, an ideal location with access to major markets, and a thriving small business support community.

 If you're ready to start your new venture in one of the country’s fastest-growing economies, consider setting up your Illinois business as an S corporation (S corp). An S corp can prove advantageous in terms of both tax savings and other benefits offered by the state. 

This guide will walk you through the process of forming your Illinois S corp as well as everything you must do to keep it in good standing.

Want to form an S corp elsewhere? Check out our other How to Start an S Corp guides to learn more.

Recommended: If you have at least $60,000 in net earnings, an S corp may offer tax advantages. Let Northwest start your S corp today.

Learn how to start an S corporation in Illinois

Factors to Consider Before Starting an S Corp in Illinois

Before forming an S corp, you have to consider the following factors:

  • Is an S corporation the best strategy for your business?
  • S corporation requirements and restrictions
  • Are S corp tax advantages right for you?

Is an S Corporation the Best Strategy for Your Business?

For help with choosing the right structure for your business, visit our Choosing a Business Structure guide.

S Corporation Restrictions

S corps have several restrictions, such as being limited to one class of stock and 100 shareholders. Read our What Is an S Corporation guide for full details.

Are S Corp Tax Advantages Right for You?

An S corporation is a tax designation that can be elected by a limited liability company (LLC) or corporation. With an S corp, business owners are considered employees of the company and must receive a reasonable salary. Since all S corps technically have employees, the s corp must run payroll. 

In order to benefit from an Illinois S corp tax designation, your business needs to make enough money to offset payroll expenses. Furthermore, S corps are beneficial for business owners who take large distributions in addition to their salary.

To learn more about the tax advantages of an S corp, read our LLC vs. S corp guide and take a look at our S Corp tax calculator.

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How to Form an Illinois S Corp

There are two main ways to start an S corp:

  • By forming an LLC and electing S corp tax status from the Internal Revenue Service (IRS) when you request your employee identification number (EIN)
  • By forming a corporation and electing S corp status from the IRS

We recommend forming an LLC because it’s simpler and more cost-effective.

Recommended: If you have an existing LLC, visit our How to Convert an LLC to S Corp guide.

Steps for Forming an LLC and Electing S Corp Status in Illinois

Starting an Illinois LLC and electing S corp tax status is easy. You can use our guides to start an LLC with the S corp status yourself, or you can hire a service provider like Northwest to guide you through this process.

There are five basic steps to start an LLC and elect S corp status:

Step 1: Name Your LLC

Step 2: Choose a Registered Agent

Step 3: File the Articles of Organization

Step 4: Create an Operating Agreement

Step 5: Get an EIN and File Form 2553 to Elect S Corp Tax Status

Step 1: Name Your LLC

Choosing a company name is the first and most important step in starting your LLC in Illinois.

Be sure to choose a name that complies with Illinois naming requirements and is easily searchable by potential clients.

1. Follow the naming guidelines for an Illinois LLC:

  • Your name must include the phrase “limited liability company,” or one of its abbreviations (LLC or L.L.C.). If it is classified as a “low-profit LLC,” it must contain "L3C."
  • Your name cannot include words that could confuse your LLC with a government agency (FBI, Treasury, State Department, etc.).
  • Your name cannot include any of the following terms: Corporation, Corp., Incorporated, Inc., Ltd., Co., Limited Partnership, and L.P.
  • Your name must be the name under which your LLC conducts business unless you register for an assumed name.
  • Your name cannot contain any word or phrase (e.g. trust, trustee, fiduciary) that indicates or implies that your LLC is in the business of a corporate fiduciary unless permitted by the Secretary of Financial and Professional Regulation. If the LLC is organized to accept or execute trusts, the name must contain the word “trust.”
  • The name may not contain any word or phrase that is restricted by any other state statute (e.g., LLCs are not permitted to operate as banks or insurers in Illinois).
  • Your name must be distinguishable from any existing business in the state. This includes Illinois reserved names.

You can also read the Illinois state statute about LLC naming guidelines for more information.

2. Is the name available in Illinois? You can use the business name search on the Illinois Secretary of State website to see if your desired LLC name is available.

3. Is the URL available? We recommend checking to see if your business name is available as a web domain. Even if you don't plan to create a business website today, you may want to buy the URL in order to prevent others from acquiring it.

Find a Domain Now

Step 2: Choose Your Illinois Registered Agent

You must elect a registered agent for your Illinois LLC.

An LLC registered agent will accept legal documents and tax notices on your LLC's behalf. You will list your registered agent when you file your LLC's Articles of Organization.

Many business owners choose to hire a registered agent service. Many of these services will form your LLC for a small fee and include the first year of registered agent services for free.

Step 3: File the Illinois LLC Articles of Organization

The Illinois Articles of Organization is used to officially register an LLC.

File Your Illinois Articles of Organization

OPTION 1: File Online With Cyberdrive Illinois

File Online

- OR -

OPTION 2: File Form LLC-5.5 by Mail

Download Form

State Filing Cost: $150 online and $75 by mail, payable to the Secretary of State (Nonrefundable)

Mailing Address:
Department of Business Services
Limited Liability Division
501 S. Second St., Rm. 351
Springfield, IL 62746

Step 4: Create an LLC Operating Agreement

An LLC operating agreement is a legal document that outlines the ownership and member duties of your LLC.

For more information, read our LLC Operating Agreement guide.

Our operating agreement tool is a free resource for business owners.

Step 5: Get an EIN and Complete Form 2553 on the IRS Website

An EIN is a number that is used by the US Internal Revenue Service (IRS) to identify and tax businesses. It is essentially a Social Security number for a business.

EINs are free when you apply directly with the IRS.

Elect S Corp Tax Status
During the online EIN application, the IRS will provide a link to Form 2553, the Election By a Small Business form.

Visit our Form 2553 Instructions guide for detailed help with completing the form.

This is the form to elect S corp tax status for your LLC:

Screenshot of IRS online EIN application.

Ready to start saving on your taxes?

We recommend using a formation service to start your Illinois S corp for you, so you can focus on the things that matter most - growing you business.

Keep Your Illinois S Corp Compliant

After you elect to have the IRS tax your LLC as an S corp, you need to follow state and local laws to ensure your business remains in good standing with the state. All Illinois S corps must file an annual report each year and obtain a state tax ID number in order to pay Illinois state taxes. 

Illinois S Corp Annual Report

Even though the IRS taxes your LLC as an S corp, you must still file an LLC annual report with the Illinois Secretary of State. This report allows the state to track tax payments and collect up-to-date information on any changes to your business’s address or registered agent. 

You must pay the filing fee and file your annual report before the first day of the month in which you initially registered your LLC. If you registered your business on July 10, 2017, for example, your annual report will be due before July 1 every year. Even if your business doesn’t make a profit or undergo any changes, you still need to file an annual report each year. Failure to file this report on time can result in a penalty and even the dissolution of your business by the state.

Read our Illinois Annual Report guide for step-by-step instructions.

Illinois S Corp Taxes

S corporations benefit from pass-through taxation, meaning the business’s profits pass-through to S corp owners’ individual tax returns. S corp owners make money from their reasonable salary and distributions, and Illinois S corp owners can expect to pay the following taxes:

Federal Self-Employment Taxes

Self-employment taxes cover social security and medicare. The self-employment tax rate is 15.3%, and money you take as salary will be subjected to the self-employment tax. However, distributions are not subjected to this tax.

Federal Income Taxes

Your federal income taxes will depend on your tax bracket, and the cutoffs for individual tax brackets as well as the percent owed will change each year. Both your salary and distributions are subjected to federal income tax.

Illinois Income Taxes

Illinois has a flat income tax rate of 4.95%. This means your state income tax rate will remain at 4.95% no matter how much income you earn in a given year. 

Many states have a graduated income tax rate that varies by an individual’s income bracket. Illinois’s 4.95% income tax rate falls squarely in the middle when compared to income taxes in other states.

Illinois State Tax ID Number

You’ll need to register your business with the Illinois Department of Revenue to receive a state tax ID number and pay your taxes. 

Illinois Personal Property Replacement Tax

Illinois S corps also must pay a 1.5% tax on their business’s net income to the Illinois Department of Revenue. Visit the Illinois General Assembly website to read more about the Illinois Personal Property Replacement Tax.

Illinois Sales and Use Tax

Illinois has a 6.25% state sales tax. Local jurisdictions may levy an additional tax on top of this, but the state caps local sales tax rates at 4.75%. Illinois businesses may need to pay state sales taxes at multiple times throughout the year. Visit the Illinois Department of Revenue website to learn more.

Additional State Taxes

The Illinois Department of Revenue outlines numerous other state-specific taxes your business may have to pay, depending on its industry, number of employees, and location. Some examples of these additional taxes include:

  • Charitable Games Tax
  • Electricity Excise Tax
  • Gas Tax
  • Hotel Operators’ Occupation Tax
  • Liquor Gallonage Tax
  • Telecommunications Tax

Visit the Illinois Department of Revenue website for more information.

Illinois Local Taxes

Local jurisdictions in Illinois may have additional rules governing businesses in the area. Whether your business operates in Chicago, Aurora, or a smaller city, local taxes and permits may apply to your business. Make sure you familiarize yourself with any local laws that can impact your business’s operations and tax obligations.

Start an Illinois S Corp FAQ

An S corporation (S corp) is a tax designation that an LLC or a corporation can elect.

No. The default taxes for an LLC and taxes for an S corp are not the same.

With an S corp, owners pay personal income tax and self-employment tax on a predetermined salary. They may then withdraw any remaining profits from the business as a “distribution,” which isn’t subject to self-employment tax.

With an LLC, all company profits pass through to the owners’ personal tax returns, and then the owners must pay personal income tax and self-employment tax on the entire amount.

S corp owners are required to earn a “reasonable” salary, which basically means a fair market rate based on the individual’s qualifications as well as their duties and responsibilities at the company. The purpose of this requirement is to prevent S corp owners from paying themselves an artificially low salary in order to pay less self-employment tax.

A distribution is a dividend that a shareholder/owner can take from the business profits that remain after a company pays all of its employee salaries. Shareholders must pay personal income tax on distributions, but distributions aren’t subject to self-employment tax.

LLCs and corporations that operate under a “doing business as” (DBA) name can choose the S corp election.

Illinois has many healthy industries, including manufacturing, agriculture, energy production, and more. You can structure your business as an S corp in all kinds of industries as long as it meets the S corp requirements set by the IRS.

You should always start your business where you plan to operate. Each state has its own tax structure, incentives, and business support systems to consider. By forming your S corp in Illinois, you can benefit from the state’s low tax rates and thriving economy.

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