Illinois requires "Limited Liability Company" or "LLC" in your name. Can't abbreviate to "L.L.C." with periods - must be "LLC" without periods. Illinois rejects 22% of LLC names for formatting errors alone.
Illinois LLC Name Requirements
Must contain "Limited Liability Company" or "LLC".
Can't use "L.L.C." with periods - Illinois specific rule.
Can't be same as or deceptively similar to existing Illinois entity.
Restricted words need proof: Bank, Insurance, Attorney, University, Engineer, Architect require licenses.
Illinois Name Availability Search
Search Illinois Secretary of State database at apps.ilsos.gov/businessentitysearch.
Check exact name and phonetic variations.
Database searches: Active corporations, LLCs, limited partnerships, assumed names.
Updated real-time. Free unlimited searches.
Availability vs Similarity
Illinois uses "deceptively similar" standard, not just "identical".
Examples: "Chicago Consulting LLC" vs "Chicago Consultancy LLC" - likely rejected.
"ABC Marketing LLC" vs "ABC Media LLC" - different industries, likely approved.
"TechStart Illinois LLC" vs "TechStart LLC" - probably rejected.
When in doubt, choose a more distinctive name.
Common Illinois Rejections: Including periods in LLC ("L.L.C."). Using "Limited" or "Company" alone without "Limited Liability Company". Too similar to existing name. Name contains "Chicago" but business isn't located in Chicago (restricted). Using professional terms (CPA, Law) without license. Check carefully before $150 filing.
Name Reservation
Reserve name for 90 days before filing Articles of Organization.
Cost: $25 online or by mail. File Form LLC-1.15.
Approval: 2-5 business days online, 2 weeks by mail.
Can extend once for additional 90 days - another $25 fee.
Reserves name while you prepare documents or raise capital.
Trademark Search Before Illinois Filing
Illinois approval doesn't check trademarks.
Search USPTO database separately at tmsearch.uspto.gov.
Check federal trademarks in your industry. Illinois only checks state business registry.
Federal trademark trumps state LLC name - can force name change even after approval.
Filing Articles of Organization
File Form LLC-5.5 online or by mail.
You'll need: LLC name with "LLC" designator, principal office address, registered agent Illinois address, organizer name and address.
Filing fee: $150 online or $170 mail.
Processing: 5 business days online, 8-10 weeks mail.
Expedite: $100 fee for 2-day processing.
Illinois doesn't require publication (unlike NY). No newspaper publication fees. File Articles of Organization, pay $150, done. Saves $1,000-2,000 compared to New York LLC formation. One reason Illinois is popular for startups.
Annual Report Requirements
File annual report each year by anniversary month.
Due during month LLC was formed - formed March means March annual report.
Fee: $75/year. File online at Illinois Business Services portal.
Late penalty: $200 + $50/month late. Dissolved after 2 years non-filing.
Assumed Name (DBA) in Illinois
Want to use a name different from legal LLC name? File assumed name.
Example: "Smith Holdings LLC" operates as "Chicago Coffee Shop".
File at county level - each county has own requirements.
Cook County (Chicago): File with County Clerk, publish in newspaper. Cost: $50 filing + $75-150 publication.
When Assumed Name Needed
Operating under different name than LLC name. Using abbreviation or shortened version.
Multiple business lines under one LLC.
Example: "ABC Ventures LLC" with assumed names "FastFood Chicago" and "QuickClean Services".
One LLC, multiple DBAs - file separately for each.
Cook County Publication Requirement: Assumed names in Cook County must be published in newspaper within 10 days. Cost: $75-$150 depending on newspaper. Failure to publish means assumed name is invalid. Law firms often miss this - verify compliance to avoid losing name rights.
Illinois Name Change After Formation
File Articles of Amendment (Form LLC-5.10).
Include: Current name, new name, date of amendment, authorized signature.
Fee: $150 (same as formation). Processing: 5 business days online.
You'll need to update: IRS (EIN), bank accounts, contracts, website, marketing materials.
Allow 3-4 weeks total to update everything.
Domain Strategy
Register domain before LLC filing.
If YourName.com is unavailable, reconsider your LLC name.
Alternatives: YourNameLLC.com, GetYourName.com, YourNameChicago.com.
Cost: $12-15/year for .com.
Check domain simultaneously with Illinois name search to ensure digital presence matches legal name.
Costs Summary
Name availability search: Free. Name reservation (optional): $25.
Articles of Organization: $150 online or $170 mail. Expedited processing (optional): $100.
Registered agent service (optional): $100-300/year. Annual report: $75/year. Domain: $12/year.
Assumed name (if needed): $125-200 Cook County.
Total first year: $237-850 depending on options.
Illinois vs Other States
Advantages: No publication requirement (saves $1,000+ vs NY). Online filing available. Real-time database search.
Disadvantages: Higher annual report fee ($75 vs $50 many states). Slower processing than Delaware.
Can't use periods in "LLC" - unique to Illinois.
Choose based on: Where you operate (pick that state), privacy needs (Wyoming, Delaware), or filing cost.
Trademark Lens checks Illinois LLC name availability and trademark conflicts - verify before paying $150 Illinois filing fee.