naming rulesUpdated 2026-03-31
Illinois LLC Name Rules
# Illinois LLC Naming Rules & Requirements (2026)
## Required Designator
Your Illinois LLC name must include one of three required designators: **Limited Liability Company**, **LLC**, or **L.L.C.** under 805 ILCS 180/1-10. This designation is mandatory and must appear exactly as written in your Articles of Organization. The Secretary of State will reject any filing that omits or alters the required language.
The designator signals to the public and creditors that your business has limited liability protection under Illinois law. You cannot substitute similar-sounding abbreviations or create variations—only the three approved forms satisfy the statute.
### Placement Flexibility
You can position the designator at the beginning, middle, or end of your business name. Examples that all comply with Illinois law include:
- Smith Consulting LLC
- LLC Smith Consulting
- Smith LLC Consulting
The Secretary of State's online filing system will flag submissions that lack one of the three approved designator forms, so verify your exact name before submitting your Articles.
### What You Cannot Use Instead
Do not attempt to use alternative abbreviations or shortened forms. Illinois law explicitly prohibits substituting these terms for the required designator:
- "L.L.C" (missing final period)
- "Limited Liability Co." (incomplete phrase)
- "L.C." or other non-standard abbreviations
The Secretary of State applies a strict compliance standard—your designator must match one of the three approved forms exactly.
---
## Restricted Words and Phrases
Your Illinois LLC name cannot include certain words and phrases reserved for other business entity types or regulated industries. Understanding these restrictions prevents rejection during the Secretary of State's review and ensures compliance with 805 ILCS 180/1-10, 205 ILCS 620/1-9, and 205 ILCS 5/46.
### Words Reserved for Other Entity Types
You cannot use **Corporation**, **Corp.**, **Incorporated**, **Inc.**, **Ltd.**, **Co.**, **Limited Partnership**, or **LP** in your LLC name under 805 ILCS 180/1-10. These designators are exclusive to corporations and limited partnerships. The Secretary of State will reject any LLC name containing these terms because they misrepresent your entity's legal structure and create confusion about liability protections.
### Banking and Financial Services Words
You cannot use **Bank**, **Banker**, or **Banking** without separate approval under the Illinois Banking Act (205 ILCS 5/46). Similarly, **Trust**, **Trustee**, and **Fiduciary** require separate approval under the Corporate Fiduciary Act (205 ILCS 620/1-9).
If your business legitimately operates in these regulated sectors, you must obtain the required license or authorization from the Illinois Department of Financial and Professional Regulation before the Secretary of State will approve your LLC name. Contact the Limited Liability Division at (217) 524-8008 to determine whether your proposed name requires additional approval.
### Insurance and Assurance Terms
Words indicating **Insurance** or **Assurance** are restricted under 805 ILCS 180/1-10 and require separate regulatory approval from the Illinois Department of Insurance. These terms signal participation in the insurance industry, which is subject to distinct licensing and oversight requirements in Illinois.
You cannot use them in your LLC name without first obtaining the necessary insurance regulatory authorization. If your business will provide insurance services, you must obtain a separate insurance license before adopting a name containing these words.
### Summary of Prohibited Words
| Category | Prohibited Terms |
|---|---|
| Entity Type | Corporation, Corp., Incorporated, Inc., Ltd., Co., Limited Partnership, LP |
| Banking | Bank, Banker, Banking |
| Fiduciary | Trust, Trustee, Fiduciary |
| Insurance | Insurance, Assurance |
---
## Distinguishability Standard
Your Illinois LLC name must be **distinguishable** from all domestic and foreign LLCs, corporations, assumed names, and reserved or registered names already on file with the Illinois Secretary of State. This means you cannot use a name that is identical or confusingly similar to an existing business entity record in the state system.
### How the Distinguishability Test Works
Illinois does not require exact uniqueness—only that your name be distinguishable in the Secretary of State's records. The Secretary of State applies a practical similarity test, meaning minor differences in punctuation, spacing, or articles ("a," "the") may not satisfy the distinguishability requirement.
You should search the [Illinois business entity database](https://apps.ilsos.gov/businessentitysearch/) before filing your Articles of Organization to confirm your proposed name is available. A name that appears available when you search may still be rejected if another entity files for the same name before your Articles are processed.
### Entities Covered by the Distinguishability Requirement
Your name must be distinguishable from:
- Domestic LLCs already formed in Illinois
- Foreign LLCs admitted to transact business in Illinois
- Illinois corporations
- Assumed names (DBAs) on file with the Secretary of State
- Reserved or registered names held by other applicants
### Three-Year Unavailability Rule for Dissolved LLCs
If an LLC is administratively dissolved by the Secretary of State, that name becomes unavailable for reuse for **three years** from the date of dissolution. This prevents former business owners from immediately re-registering a dissolved entity's name and potentially confusing creditors or customers.
You cannot reserve or file articles under a name that was administratively dissolved within the past three years. Check the Secretary of State's database to confirm the dissolution date before selecting your name.
---
## Name Search and Availability Check
You must search Illinois's business entity database before filing your LLC articles and verify that your chosen name is distinguishable from all existing domestic and foreign LLCs, corporations, assumed names, and reserved names on file with the Secretary of State.
### Search the Illinois Business Entity Database
The Illinois Secretary of State maintains a free, public business entity search at **https://apps.ilsos.gov/businessentitysearch/**. You can search by entity name, registered agent name, or filing number to check availability instantly. This search covers all active and inactive entities registered with the state.
The search results will show you the exact name, entity type, status, and filing date of any matching entities. If you find an identical or similar name, you will need to choose a different name or contact the existing entity owner to negotiate a name change.
### Important Timing Consideration
The Secretary of State does not hold names while you search—another business can file for your desired name while you are still researching. If you want to lock in a name before filing your Articles of Organization, you can reserve the name for 90 days by paying a $25 reservation fee.
### Verify Your Name Meets All Requirements
Before filing, confirm your proposed name:
- Includes **Limited Liability Company**, **LLC**, or **L.L.C.** as the required designator
- Is distinguishable from all existing registered entities
- Does not contain prohibited words (Corporation, Corp., Inc., Ltd., Co., Limited Partnership, LP)
- Does not include restricted industry terms (Insurance, Bank, Trust, etc.) without separate approval
---
## Name Reservation
You can reserve an Illinois LLC name for **90 days** by paying a **$25 fee** to the Secretary of State. Reservation protects your chosen name while you prepare formation documents, and you may renew the reservation if you need additional time.
### How to Reserve Your Name
File a name-reservation request through the Illinois Secretary of State's online system at **https://apps.ilsos.gov/llcarticles/index.jsp**, or contact the Limited Liability Division at **(217) 524-8008**. The Secretary of State will confirm availability and hold the name for your exclusive use during the 90-day period.
The 90-day reservation period begins on the date the Secretary of State receives and approves your reservation request. You can renew the reservation if you need additional time to organize your LLC or wait for financing.
### Naming Requirements You Must Meet
Your reserved name must satisfy Illinois LLC naming rules under 805 ILCS 180/1-10. The name must:
- Include **Limited Liability Company**, **LLC**, or **L.L.C.** as a required designator
- Be distinguishable from all domestic and foreign LLCs, corporations, assumed names, and reserved or registered names already on file with the Secretary of State
- Avoid restricted words: *Corporation*, *Corp.*, *Incorporated*, *Inc.*, *Ltd.*, *Co.*, *Limited Partnership*, or *LP*
Words indicating insurance, assurance, banking, or corporate-fiduciary authority are also restricted. If your name includes *trust*, *trustee*, *fiduciary*, *bank*, *banker*, or *banking*, you must obtain separate approval from the appropriate state regulator before the Secretary of State will approve your reservation.
### What Happens After Reservation Expires
If you file your Articles of Organization before the reservation expires, your name is protected and the reservation is automatically cancelled. If the reservation lapses without filing, the name becomes available to other applicants, and you must reserve it again or choose a different name.
---
## DBA and Assumed Names
If you want to operate your Illinois LLC under a name different from your registered LLC name, you must file an assumed name (also called a "DBA" or "doing business as" name) with the Illinois Secretary of State. This requirement applies only to LLCs—sole proprietors file assumed names at the county level, not with the state.
### Filing Your Assumed Name
You file your assumed-name registration directly with the **Illinois Secretary of State, Department of Business Services, Limited Liability Division**. Standard processing takes approximately 10 days; expedited service (24 hours) is available if you need faster approval for an additional expedited fee.
You can file your assumed name online through the Secretary of State's system at **https://apps.ilsos.gov/llcarticles/index.jsp**, by mail, or by phone at (217) 524-8008.
### Assumed Name Requirements
Your assumed name must also include the LLC designator (**LLC**, **Limited Liability Company**, or **L.L.C.**) and must be distinguishable from other registered names. The assumed name cannot be identical to or confusingly similar to any domestic or foreign LLC, corporation, assumed name, or reserved name already on file with the Secretary of State.
### Fee Schedule by Year
Your assumed-name filing fee depends on the calendar year in which you file:
| Year Ends In | Fee |
|---|---|
| 0 or 5 | $150 |
| 1 or 6 | $120 |
| 2 or 7 | $90 |
| 3 or 8 | $60 |
| 4 or 9 | $30 |
For example, if you file in 2026 (ends in 6), you pay $120. If you file in 2027 (ends in 7), you pay $90.
### Duration and Renewal
Your assumed name remains effective until the first day of your LLC's anniversary month in the next calendar year evenly divisible by five, at which point it must be renewed for another five-year period. You should verify renewal status with the Secretary of State to avoid lapses in protection.
### Consequences of Operating Without Filing
If you operate under an assumed name without filing with the Secretary of State, you may face penalties and lose the ability to enforce contracts or sue in your LLC's assumed name. Always file your assumed name before conducting business under that name.
### Sole Proprietors: County Filing Required
If you operate as a sole proprietor (not an LLC), you cannot file your assumed name with the Illinois Secretary of State. Instead, file with your **county clerk or recorder**. Only LLCs file assumed names at the state level in Illinois.
---
## Filing Authority and Contact Information
The Illinois Secretary of State, Department of Business Services, Limited Liability Division, oversees all LLC filings in Illinois. You can file your Articles of Organization online, by mail, or in person at one of two offices.
### Secretary of State Contact Details
**Illinois Secretary of State**
Department of Business Services
Limited Liability Division
**Phone:** (217) 524-8008
**Mailing Addresses:**
- **Springfield Office:** 501 S. Second St., Rm. 350, Springfield, IL 62756
- **Chicago Office:** 69 W. Washington St., Ste. 1240, Chicago, IL 60602
**Website:** https://www.ilsos.gov/
### Online Filing
You can file your Articles of Organization online through the Secretary of State's LLC filing portal at **https://apps.ilsos.gov/llcarticles/index.jsp**. Online filing is the fastest method and allows you to track your submission status in real time. The online filing system provides confirmation of approved Articles within one business day for standard processing.
### Name Search and Reservation
Before filing, search existing business names at **https://apps.ilsos.gov/businessentitysearch/** to ensure your proposed LLC name is distinguishable from all registered entities. You can reserve an available name for 90 days by paying a $25 reservation fee through the same portal.
### Document Submission Methods
You may submit your Articles of Organization online, by mail to either the Springfield or Chicago address, or by phone. The Secretary of State's office processes filings and issues your Certificate of Organization once your documents meet all statutory requirements under 805 ILCS 180/5-5.
If you need immediate confirmation, the Secretary of State offers expedited processing for an additional fee.
---
## Key Takeaways for Your LLC Name
Your Illinois LLC name must include a required designator, avoid restricted words, and be distinguishable from existing entities on file with the Illinois Secretary of State. You can reserve a name for 90 days for $25, and you must search the state database before filing your Articles of Organization.
### Required Designator
Your LLC name must end with **Limited Liability Company**, **LLC**, or **L.L.C.** under 805 ILCS 180/1-10. You cannot abbreviate or modify this requirement—the Secretary of State will reject your Articles of Organization if the designator is missing or incorrect.
### Prohibited Words
You cannot use **Corporation**, **Corp.**, **Incorporated**, **Inc.**, **Ltd.**, **Co.**, **Limited Partnership**, or **LP** in your LLC name under 805 ILCS 180/1-10. These terms imply a different business structure and will cause the Secretary of State to reject your filing.
Certain industry-specific words are also restricted. You cannot use **Insurance**, **Assurance**, **Bank**, **Banker**, **Banking**, **Trust**, **Trustee**, or **Fiduciary** without separate approval under 805 ILCS 180/1-10, 205 ILCS 620/1-9, and 205 ILCS 5/46. If your business operates in these sectors, contact the Illinois Secretary of State at (217) 524-8008 or the Illinois Department of Financial and Professional Regulation to determine whether you need additional licensing or approval.
### Distinguishability Requirement
Your name must be distinguishable from all domestic and foreign LLCs, corporations, assumed names, and reserved or registered names already on file with the Secretary of State. You cannot use a name that is confusingly similar to an existing entity, even if the other entity uses a different designator.
If an LLC was administratively dissolved, its name remains unavailable for three years after the dissolution notice. Check the Secretary of State's business entity search at **https://apps.ilsos.gov/businessentitysearch/** before you file.
### Name Reservation
You can reserve an available name for 90 days by paying a $25 fee to the Illinois Secretary of State. Reservation gives you time to prepare your Articles of Organization without risk that someone else will claim the name. You may renew the reservation if you need additional time.
### Assumed Names (DBAs)
If you want to operate under a name different from your LLC's legal name, you must
## Related Pages
- [Illinois Llc Formation](/states/illinois/how-to-start-an-llc/)
- [Illinois Llc Cost](/states/illinois/llc-cost/)
- [Illinois Llc Taxes](/states/illinois/llc-taxes/)
- [Illinois Annual Requirements](/states/illinois/llc-annual-report/)
- [Illinois Registered Agent](/states/illinois/registered-agent/)