A business name in Illinois has to pass one gate before anything can be filed under it: distinguishability from every name already on the register at Illinois Secretary of State. illinois business name search is how you run that test yourself, free, before paying a filing fee on a name the state will bounce. This page covers the official check, how the register compares names, and the two other clearances - trademark and domain - the register deliberately does not do.
How the register judges a name
The test is distinguishability on the record: your proposed name against every active - and in some states recently dissolved - name at Illinois Secretary of State. Differences the statute treats as insufficient are the classic traps: punctuation, capitalisation, spacing, an entity ending like LLC versus Inc, and often articles and conjunctions. The official search linked from our Illinois page lets you run the comparison the way an examiner will, and searching stems and variants rather than the exact string is what surfaces the near-misses before the state does. Illinois still runs corporation and LLC records as visibly separate series in one search, and its fee schedule is unusually public: the charges sit in the Business Corporation Act itself rather than a rate card.
What a clear search does not clear
Availability at the register is a Illinois filing question, nothing more. It does not clear trademarks - a federally registered mark can shut down a name the register happily accepted - and it does not touch domains or social handles. The trademark search happens at the USPTO and the register will not warn you; running both before printing anything is the discipline that saves rebrands. Conversely, owning a trademark does not reserve you a register name: the two systems simply do not talk.
Reserving the name, or moving fast instead
Most states, Illinois's rules included on the register's own pages, offer a paid name reservation for a fixed window - useful when formation is weeks away, unnecessary when you can simply file now, since the filing itself is what actually takes the name. If the name is in use as a trade name rather than an entity, the assumed-name records tell that story separately. The one reliable rule: the register's record at Illinois Secretary of State is the referee, and checking it costs nothing.
Questions people ask about illinois business name search
Is the Illinois name search free?
Yes; the availability check runs on the register's own search at Illinois Secretary of State, linked from our Illinois page. Reservation, where offered, is the paid option - checking is not.
What makes a name 'too similar'?
The statute's distinguishability rules: punctuation, spacing, capitalisation and entity endings usually do not distinguish. The register's own guidance states the local test.
Does availability mean I own the name?
No; only an accepted filing takes it, and trademark rights are a separate federal question the register never checks.
Can I reserve a name before forming?
Where Illinois offers reservation, the register's pages publish the term and fee; filing the formation is the other way to take the name.