Form a S-Corp in Illinois

Everything you need to know about forming a S-Corp in Illinois. Filing fees, requirements, timeline, and step-by-step guidance.

$175
Filing Fee
7-10 business days
Processing Time
0
Required
Registered Agent

How to File

1

Choose Corporate Name

Select a unique name ending with 'Corporation', 'Corp.', 'Incorporated', or 'Inc.' Check availability through Illinois Secretary of State database.

30 minutes

2

Appoint Registered Agent

Designate a registered agent with Illinois address to receive legal documents. Can be yourself, employee, or professional service.

15 minutes

3

File Articles of Incorporation

Submit Articles of Incorporation with Illinois Secretary of State including corporate name, registered agent, shares authorized, and incorporator information.

45 minutes

4

Obtain EIN from IRS

Apply for Federal Employer Identification Number (EIN) from the IRS online, by phone, or mail for tax purposes.

15 minutes

What's Next After Filing

Once your S-Corp is officially formed, you'll want to complete these important steps:

  • File Form 2553 for S-Corp ElectionSubmit IRS Form 2553 within 75 days of incorporation to elect S-Corporation tax status. All shareholders must sign the form.
  • Create Corporate BylawsDraft corporate bylaws outlining internal governance, shareholder rights, director duties, and meeting procedures.
  • Hold Organizational MeetingConduct first board meeting to adopt bylaws, issue stock certificates, elect officers, and complete other organizational matters.

Advantages

  • Pass-through taxation avoids double taxation on corporate profits
  • Limited liability protection for shareholders from business debts
  • Enhanced credibility and professional image for business operations
  • Ability to have up to 100 shareholders with voting and non-voting shares

Considerations

  • Strict IRS requirements including one class of stock and US citizen shareholders only
  • Required payroll taxes on owner-employee reasonable salaries
  • More complex tax filings and corporate formalities than sole proprietorship

Annual Obligations

Franchise Tax:$0*
Annual Report Fee:$75
Report Due:First day of anniversary month
* Annual report must be filed by the first day of the anniversary month of incorporation. No Illinois franchise tax for S-Corporations.
Last verified: December 2025Source

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Form S-Corporation in Illinois | 2025 Filing Guide & Fees | OpenChamber