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Missouricorporate tax inIllinois
High — top rate 8% or higher

Illinois

Top Rate
9.5%
Rate Structure
Flat
Franchise Tax
Yes
Gross Receipts Tax
No
S-Corp Recognized
Yes

Corporate Income Tax Rate at a Glance

Illinois's top corporate income tax rate is 9.5%, applied as a flat rate. This places Illinois in the "High (8% or higher)" tier among U.S. states.

Rate Structure (Flat vs. Graduated)

Combined top rate of 9.5%: 7.0% corporate income tax plus 2.5% Personal Property Replacement Tax (PPRT) on C-corporations. S-corporations, partnerships, and LLCs (taxed as partnerships) pay 1.5% PPRT only.

Franchise Tax / Annual Privilege Tax

Illinois imposed a franchise tax (paid-in capital tax) but the tax has been substantially reduced and partially phased out. A $25 minimum applies; additional tax based on paid-in capital still applies for some entities.

S-Corp & Pass-Through Treatment

Illinois recognizes federal S-corp election but imposes the 1.5% Personal Property Replacement Tax on S-corp net income at the entity level. Pass-through entities may also elect to pay PTE tax at 4.95% under Illinois's PTE workaround.

Official State Revenue Department

For current corporate tax rules in Illinois, consult the state's official source at https://tax.illinois.gov/. Rates and rules change annually — verify with a qualified tax professional before taking any action.

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Related guides

Illinois Department of Revenue: https://tax.illinois.gov/
Law last updated: 2025Row last reviewed: May 9, 2026

Corporate income tax rates change frequently as states enact reform packages and phase-down schedules. Always verify current rates with the state's department of revenue and your tax advisor before making business decisions. This information is for educational purposes only and is not tax or legal advice.