Step-by-step guide to forming a S-Corp in Illinois. Filing fee ($150), requirements, timeline, taxes, and what international founders need to know.
Midwest Finance & Commerce Hub
Step-by-step process for international founders.
Form a C-Corp or LLC first
File Form 2553 (S-Corp election) with IRS
Meet all eligibility requirements
Set up payroll for owner salary
File annual Form 1120-S
File annual report / pay annual fees in Illinois
Annual fee: $75. Due: Annually
| Cost Item | Amount | Notes |
|---|---|---|
| State filing fee | $150 | One-time, paid to Illinois SOS |
| Registered agent (Year 1) | $50–$150/yr | Required in Illinois |
| Annual report / renewal | $75/yr | Due: Annually |
| EIN (Federal Tax ID) | Free | Apply via IRS Form SS-4 |
| Operating Agreement / Bylaws | $0–$500 | DIY or attorney-drafted |
| Business bank account | $0 | Mercury or Relay recommended |
| Total Year 1 (estimated) | $325–$875 | Varies with registered agent choice |
Pass-through (but owners pay salary + save on SE tax)
IRS Form: Form 1120-S + Schedule K-1
Yes (4.95% flat)
Franchise tax: Yes (on paid-in capital)
Yes. Illinois allows non-US residents to form a S-Corp entirely remotely. You need a registered agent with a Illinois address, and you'll apply for an EIN from the IRS using Form SS-4.
No. You can form a Illinois S-Corp from anywhere in the world. However, you must maintain a registered agent with a physical Illinois address.
Standard processing: 3–7 days. Expedited processing is available for an additional fee through the Illinois Secretary of State.
Mercury and Relay are the top choices for international founders. Both open accounts fully online, require no US visit, and work well with Illinois entities.
Formation is step one. The Stack Network covers the rest of your US business journey.
Annual reports, BOI filings & state compliance deadlines — automated so you never miss one.
Stay compliant →US bookkeeping, payroll & fractional CFO for international founders.
Manage your finances →Operating agreements, IP assignments & legal document templates for US entities.
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