Tax Elections
How to Start an S Corp in Illinois: Tax Election Guide
How to start an S corp in Illinois begins with an eligible corporation or LLC and a valid federal S election. The election changes tax treatment; it does not itself create the Illinois entity. Check the legal structure, shareholders and effective date before filing.
How to start an S corp in Illinois begins with an eligible corporation or LLC and a valid federal S election. The election changes tax treatment; it does not itself create the Illinois entity. Check the legal structure, shareholders and effective date before filing. IRS S corporation requirements.
Nonresident aliens cannot be shareholders in an S corporation. For an international founder, that eligibility test should come before any promised tax savings or formation package recommendation.
How to start an S corp in Illinois: form or review the entity
For a new LLC, follow the Illinois LLC formation guide. An existing out-of-state entity may instead need Illinois foreign registration, depending on its activity. Do not form a second company merely because the first is considering a different tax election.
Review ownership records and governing agreements. The IRS requirements include limits on shareholder types and numbers and the permitted class of stock. Obtain a qualified review if the company has investors, unusual distribution rights or entity owners.
Prepare Form 2553 and retain the acceptance
Use the actual legal name, EIN, tax-year information and intended election date. Obtain the required consents and follow the Form 2553 instructions. The general timing window is the preceding tax year or no later than two months and fifteen days after the intended tax year begins.
Late-election relief is conditional. Keep submission evidence and the IRS's response in the permanent tax file. Reconcile the approved effective date with the payroll and accounting treatment used for that year.
Plan Illinois tax separately from federal pass-through treatment
Illinois S corporations generally use Form IL-1120-ST under the state's applicable filing rules. Illinois also imposes a 1.5% replacement tax on S corporation net income, subject to the state's calculation rules. Federal pass-through treatment does not mean the entity has no Illinois tax. Illinois pass-through guidance, state tax rates.
| Workstream | Record to maintain |
|---|---|
| Federal election | Filed Form 2553 and IRS response |
| Payroll | Wage records and employment-tax filings |
| Illinois entity return | Applicable IL-1120-ST and supporting schedules |
| Owner reporting | Shareholder statements and residency details |
| State company record | Annual report and agent information |
Have the preparer assess elective pass-through tax and nonresident-owner requirements separately. Those questions should not be answered solely from the federal election letter.
Decide whether the ongoing work is worthwhile
A working shareholder's compensation must be handled appropriately. Review the IRS reasonable-compensation guidance and the owner draws versus salary guide. Payments should not all be labeled distributions merely to avoid payroll.
Compare expected savings with payroll administration, bookkeeping and state tax costs using realistic revenue and profit estimates. Keep Illinois annual reporting current regardless of the tax election. If the business later closes, the Illinois termination guide covers the separate state-law exit, while final S corporation returns require their own preparation.
If an owner or the business also operates in Colorado, review the Colorado S corporation guide, particularly its state and nonresident-owner reporting distinctions.
For help with formation paperwork, contact PrimeRegister. If you prefer ordering formation assistance through Fiverr, review our LLC formation gig on Fiverr (IncorpoDesk). Confirm the package, state fees and deliverables before ordering; tax elections and tax preparation are not implied by the formation listing.
