How to Start a Corporation in Illinois

Starting a corporation in Illinois is a straightforward legal process that typically takes 10 business days and costs $150 for standard filing. Whether you are launching a tech startup in Chicago or a manufacturing business in Springfield, incorporating in Illinois gives you liability protection, tax flexibility, and credibility with customers and lenders. This guide walks you through exactly what you need, how to file, and what comes next.

What You'll Need to Incorporate in Illinois

Before you file, gather these materials:

• Business name. Must be unique and distinguishable in the Illinois Secretary of State database. Verify availability at https://apps.ilsos.gov/businessentitysearch/
• Registered agent information. An Illinois resident or authorized entity with a street address (P.O. Box alone is not accepted).
• Principal office address. Where your corporation will conduct business in Illinois.
• Incorporator details. At least one person who signs the articles (can be your agent or any adult).
• Registered agent street address. Must be identical to their business office address.
• Filing fee. $150 for standard 10 business day processing online.

Optional but useful:

• Initial bylaws (filed separately, not required at incorporation)
• Corporate operating agreement (not required, but recommended)
• Shareholder structure (who owns how many shares)

The 7 Steps to Incorporate a Corporation in Illinois

Step 1: Reserve or Confirm Your Business Name

Search the Illinois Secretary of State database at https://apps.ilsos.gov/businessentitysearch/ to confirm your name is available. A corporation name must be unique and distinguishable from all other registered entities in Illinois. The name does not need to be the same as your domain name or operating business name.

If you want to lock it down before filing, you can reserve a name for 90 days by filing Form LLC-1.15 (Name Reservation) with a $25 fee at the Secretary of State website. This is optional but useful if you need time to prepare other documents, coordinate with partners, or secure funding.

Step 2: Decide on Your Registered Agent

Every Illinois corporation must appoint and maintain a registered agent. This person (or authorized Illinois entity) is the official point of contact and receives all Secretary of State correspondence and legal documents on behalf of your corporation. The registered agent must:

• Be an individual who lives in Illinois, OR an entity authorized to conduct business in Illinois
• Have a street or road address in Illinois (no P.O. Box)
• Have that address listed as their registered office address
• Be available during business hours to receive mail

Many small business owners name themselves as the registered agent to keep costs down. This works if you maintain a stable Illinois address and check mail regularly. Others hire a professional registered agent service to handle this responsibility. If you use a service, expect to pay $100 to $300 per year, depending on the provider. Changing your registered agent costs $25 each time on Form BCA 5.10.

Step 3: Prepare Your Articles of Incorporation

Download Form BCA 2.10 (Articles of Incorporation) from the Illinois Secretary of State website at https://www.ilsos.gov/departments/business-services.html. The form is straightforward and requires:

• Corporation name (must match your search result)
• Registered agent name and Illinois street address
• Principal office address (can be the same as registered agent address)
• Incorporator name and address
• Number of authorized shares (typically 1,000 for a small business, but you can choose any number)
• Your signature or digital signature (required)

The form is one page and available as a PDF you can type into, print, and sign by hand, or you can fill it completely by hand. Type it carefully, the Secretary of State will reject forms with missing fields or illegible information.

Step 4: File Online or by Mail

You have three filing options:

Online filing (recommended for speed and confirmation): Go to https://apps.ilsos.gov/llcarticles/index.jsp. Upload your completed Articles of Incorporation form and pay the $150 filing fee by credit card. Processing time is 10 business days from submission. You receive a filing confirmation immediately and can track your application online.

Expedited online filing (24 hours): Same portal, same form, but select the expedited option at checkout. Cost is $250 total ($150 filing fee plus $100 expedite charge). Processing time is one business day. Useful if you need to close a business deal, secure a bank account, or meet a specific deadline.

Paper filing by mail: Mail your original signed Articles of Incorporation to Illinois Secretary of State, Department of Business Services, Springfield, IL 62756. Include the $150 filing fee as a check or money order. Processing takes 10 business days. This option is slower and prone to delays if documents are missing or illegible, so online filing is preferable.

Step 5: Receive Your Certificate of Incorporation

Once the Secretary of State processes your filing, you will receive a Certificate of Incorporation via email (if you filed online) or mail (if you filed by paper). This document proves your corporation legally exists and is your official receipt for the filing fee. Keep it in a safe place. You will need it to:

• Open a business bank account
• Apply for an Employer Identification Number (EIN)
• Obtain business licenses and permits
• Establish business credit

Do not lose or damage your certificate. You can request a certified copy from the Secretary of State for $1 if you need a replacement.

Step 6: Apply for an Employer Identification Number (EIN)

Even if you have no employees, you need an EIN to open a business bank account and file tax returns. Apply free online at https://www.irs.gov/ein, or by phone at 1-800-829-4933. The IRS issues your EIN immediately online. You will need:

• Your Certificate of Incorporation
• Your registered agent information
• Your principal business address
• Information about your business activities
• Your social security number or ITIN (as incorporator or principal owner)

The EIN is a nine-digit number formatted as XX-XXXXXXX. Write it down and save it immediately. You cannot look it up later using your social security number.

Step 7: Register for Illinois Taxes and Open a Business Bank Account

Register with the Illinois Department of Revenue at https://tax.illinois.gov/ using Form REG-1 through their MyTax Illinois portal. Registration is free and processes in one to two business days online. You will need this registration to:

• Collect and remit sales tax (if applicable)
• Pay corporate income tax
• File payroll withholding taxes if you hire employees
• Meet state tax compliance requirements

Once you have your EIN and Certificate of Incorporation, open a business bank account at any Illinois bank or credit union. You will need your Certificate of Incorporation, EIN, and photo identification. Separate business and personal finances from day one. This protects your personal liability shield and makes accounting much easier at tax time.

Understanding Illinois Corporate Taxes

Corporations in Illinois face specific tax obligations. Understanding these upfront helps you plan your finances and avoid surprises:

• Corporate income tax: 7% on net income
• Personal property replacement tax: 2.5% on net income (combined effective rate is 9.5%)
• Franchise tax: 0.1% of Illinois paid-in capital, minimum $25. However, for filing periods beginning January 1, 2025 and after, there is a $10,000 liability exemption, so most small corporations owe $0.
• Sales tax: 6.25% state rate (municipalities add additional sales tax ranging from 0% to 3% depending on your city)

Individual shareholders in your corporation pay Illinois personal income tax at 4.95% flat rate on dividends they receive. This is separate from corporate taxes. Some small business owners choose S corporation tax treatment (taxed as a partnership) to reduce the 9.5% combined rate. This election is made with the IRS and Illinois, not with the Secretary of State, and requires careful planning. Consult a CPA or tax attorney to understand which structure saves the most money for your specific situation.

After You Incorporate: Ongoing Requirements

Annual Report Filing

Every year, before the first day of your corporation's anniversary month (the month you filed the Articles of Incorporation), you must file an Annual Report on Form BCA 14.05-D with the Illinois Secretary of State. The fee is $75. You can file online at https://apps.ilsos.gov/llcarticles/index.jsp, the same portal where you filed your Articles.

The Secretary of State mails a pre-filled report to your registered agent about 45 days before the due date, so watch for it. If you miss the deadline, a $100 late penalty applies if you file more than 60 days after the due date. Missing the annual report can result in administrative dissolution of your corporation, meaning it loses its legal standing and no longer exists as a separate entity. Reinstatement requires additional filings and fees.

Corporate Bylaws and Minutes

Although you do not file bylaws with the state, you should adopt bylaws that govern how your corporation operates (board meetings, shareholder votes, officer roles, etc.). Keep meeting minutes to document corporate decisions and protect your liability protection. If someone sues your corporation and questions whether it truly exists as a separate entity, courts look to bylaws and minutes as proof of legitimate corporate operation.

Changing Your Registered Agent or Address

If your registered agent or principal office address changes, file Form BCA 5.10 or BCA 5.20 (Change of Registered Agent or Office) with the Secretary of State. The fee is $25. Do not simply update your records without notifying the Secretary of State, mail sent to an old address will be marked undeliverable and you may miss important notices.

Common Mistakes to Avoid

Mistake 1: Using a P.O. Box for registered agent address. The Secretary of State's mail system depends on a physical street delivery address. Using a P.O. Box will result in rejection of your filing. Even if it somehow gets accepted, mail will be misdirected and you will miss legal documents.

Mistake 2: Skipping or missing the annual report deadline. Hundreds of Illinois corporations are dissolved each year for not filing their annual report on time. Once dissolved, your corporation cannot enter contracts, own property, or sue in court. Dissolution also damages your business credit and personal reputation. Set a calendar reminder for the month before your anniversary month and check email for the Secretary of State's pre-filed report.

Mistake 3: Mixing personal and business finances. The primary reason to incorporate is liability protection. If you deposit business checks into your personal account and pay business expenses from personal funds, a court may pierce the corporate veil and hold you personally liable for business debts. Open and maintain a separate business bank account from day one.

Mistake 4: Not obtaining an EIN. You need an EIN even if you have no employees. Without it, you cannot open a business bank account or file federal tax returns. Some banks will not recognize your corporation without an EIN.

Mistake 5: Choosing an unreliable registered agent. Do not list an out-of-state friend or someone without a stable Illinois address. If they move or become unreachable, critical legal documents could be missed. Use a local agent or a professional registered agent service.

Mistake 6: Assuming incorporation replaces licenses and permits. Incorporation creates the legal entity, but it does not replace industry-specific licenses, permits, or registrations. If you operate a bar, daycare, pharmacy, insurance agency, or other regulated business, you need separate state and local licenses. Research your industry's requirements before or immediately after incorporation.

Illinois-Specific Resources

Keep these links handy for reference:

• Illinois Secretary of State, Department of Business Services: https://www.ilsos.gov/departments/business-services.html
• Business entity search: https://apps.ilsos.gov/businessentitysearch/
• Online filing for corporations: https://apps.ilsos.gov/llcarticles/index.jsp
• Illinois Department of Revenue: https://tax.illinois.gov/
• IRS EIN application: https://www.irs.gov/ein
• Illinois Small Business Development Center: https://sbdc.illinois.gov/
• SBA Illinois district office: https://www.sba.gov/district/illinois

When to Consult a Professional

This guide covers the basic filing steps. However, consider consulting a business attorney or CPA if:

• You have multiple founders or complex ownership structures
• You plan to take on investors or venture capital
• Your industry is heavily regulated (finance, healthcare, real estate, food service)
• You are uncertain whether a corporation or LLC is the right structure for your business
• You need help drafting bylaws, shareholder agreements, or operating agreements
• You have questions about S corporation election or other tax strategies

A business attorney typically charges $500 to $1,500 for incorporation setup and advice. A CPA can advise on tax strategy and ensure you are meeting all filing obligations. Both are investments in getting your foundation right and can save you thousands in tax liability and legal problems later.

Key Takeaway

Incorporating in Illinois takes three main steps: file your Articles of Incorporation with the Secretary of State ($150, 10 business days), get an EIN from the IRS, and register with the Illinois Department of Revenue. After that, your only recurring obligation is an annual $75 report filing before your anniversary month. The process is straightforward, affordable, and gives you legal liability protection that sole proprietorships do not offer. Once incorporated, maintain your liability shield by keeping finances separate and filing your annual report on time.

Disclaimer: This article is informational and does not constitute legal, tax, or accounting advice. Incorporation rules, filing fees, and tax rates are subject to change. Before incorporating, consult a qualified business attorney and CPA to ensure the corporation structure is right for your situation and to understand your specific tax obligations and benefits.