Yes — Illinois authorizes Series LLCs
Illinois is one of about 20 US states that explicitly authorize Series LLC structures. A Series LLC is one "master" LLC with multiple independently-walled-off "series" — each series owns its own assets and is shielded from the liabilities of every other series, like containers in a ship.
What a Series LLC actually does
A Series LLC lets you hold multiple risk-segregated assets (rental properties, IP, vehicles, separate product lines) under one filing and one annual fee, with internal liability walls between each "series." The legal theory: a creditor of Series A cannot reach the assets of Series B.
Cost in Illinois
| Standard LLC | Series LLC | |
|---|---|---|
| Filing fee | $150 | $150 (master) + sometimes per-series fee |
| Annual report | $75 | Usually one master report — but some states require per-series. |
| Registered agent | One | One for master (each series typically uses master's). |
How to form a Series LLC in Illinois
- File Articles of Organization that explicitly elect Series LLC status (or include a "series" provision per Illinois statute).
- Adopt a master Operating Agreement that authorizes the creation of separate series and lays out the firewall language.
- For each new series: adopt an addendum to the Operating Agreement; some states require filing a "designation of series" — check with the Illinois Secretary of State.
- Open a separate bank account per series (mandatory — commingling destroys the liability wall).
- Keep separate books for each series.
When the Series LLC pays off
- Multiple rental properties: Each property = one series. Tenant lawsuit on Property A cannot reach Property B.
- Multiple product lines or brands with independent liability profiles.
- Holding companies for separate IP assets.
When it does NOT pay off
- You only have one business. A standard LLC suffices.
- You operate primarily in a non-Series state. The liability walls may not be respected by that state's courts.
- You need lender financing on each series — most lenders treat each series as a separate entity for underwriting, defeating the savings.
- You want tax simplicity. Each series may file separately (state-specific guidance varies).
Caveat: not every state honors out-of-state Series LLC liability walls. If you form in Wyoming but operate in a non-Series state, that state's courts may treat all series as one entity for liability purposes. Consult a real estate or asset-protection attorney before relying on the structure for high-value assets.