SCorpDesk / 2026 S-Corp & QBI Guides / Illinois (IL) 2026 S-Corp Tax Calculator, PTET Election & Franchise Tax Guide
Illinois (IL) 2026 S-Corp Tax Calculator, PTET Election & Franchise Tax Guide
What are the 2026 S-Corp tax and PTET rules in Illinois?
In Illinois (IL), the 2026 S-Corporation election rule is: Recognizes Federal Form 2553 (Form IL-1120-ST). For the Pass-Through Entity Tax (PTET) deduction: 4.95% Illinois Pass-Through Entity Tax (PTET). Entity-level franchise/minimum tax: 1.5% Mandatory S-Corp Personal Property Replacement Tax.
In Illinois (IL), the 2026 S-Corporation election rule is: Recognizes Federal Form 2553 (Form IL-1120-ST). For the Pass-Through Entity Tax (PTET) deduction: 4.95% Illinois Pass-Through Entity Tax (PTET). Entity-level franchise/minimum tax: 1.5% Mandatory S-Corp Personal Property Replacement Tax.
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2026 Illinois (IL) S-Corporation Statutory Tax Matrix
| Illinois S-Corp Compliance Area | 2026 Statutory Rule |
|---|---|
| State S-Corp Election Recognition | Recognizes Federal Form 2553 (Form IL-1120-ST) |
| Pass-Through Entity Tax (PTET) Election | 4.95% Illinois Pass-Through Entity Tax (PTET) |
| Annual Minimum / Franchise Tax | 1.5% Mandatory S-Corp Personal Property Replacement Tax |
| Federal Section 199A QBI Deduction | Up to 23% of qualified K-1 income under Public Law 119-21 |
| Home Office & Mileage Deduction Method | Must use an IRC Section 62(c) Corporate Accountable Plan |
Frequently Asked Questions
Does Illinois require a separate state S-Corp election in 2026?
For Illinois (IL): Recognizes Federal Form 2553 (Form IL-1120-ST).
What is the Illinois S-Corp franchise or minimum tax for 2026?
In Illinois: 1.5% Mandatory S-Corp Personal Property Replacement Tax.