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Illinois has two doors for an assumed name. Which one you use depends on whether your business is a company on the Secretary of State's books. Sole owners and partnerships go to the county. LLCs and corporations go to Springfield. This page covers both, and the DBA search guide explains how lookups differ across the country.
Which office takes my assumed name?
The Assumed Business Name Act sits in the Illinois Compiled Statutes at 805 ILCS 405/1. It bars anyone from doing business under a name other than their own real name unless they file a certificate in the office of the County Clerk of the county where the business operates.
The act does not reach companies formed in Illinois. Section 4 says it does not apply to a corporation, limited liability company, limited partnership or limited liability partnership organized under Illinois law, or to one from another state that does business here lawfully. Those entities use the Secretary of State. Our Illinois DBA vs LLC comparison shows why many owners form a company first.
What goes in the county certificate?
The certificate states the name you will use and the full real names of the people who own the business. It also lists a post office address for each owner and every address in the county where the business operates. The owners sign it and acknowledge it.
If a name or address changes, or an owner is added, you file a new certificate. If the business moves to another county or opens a second location in one, the certificate goes to that county's clerk too, with its own notice.
How does the newspaper notice work?
Publication is the step people miss. You publish notice of the filing once a week for 3 consecutive weeks in a newspaper of general circulation in the county. The first notice must run within 15 days after you file. You then give the clerk proof of publication within 50 days of the filing date. The clerk issues a receipt at no extra charge.
Skip the proof and the statute treats the certificate of registration as void. A filing with no publication is therefore not a working DBA.
What if I trade without filing?
Failing to comply is a Class C misdemeanor. Each day of business in violation counts as a separate offense. The same act also says a foreign person or entity may not use an assumed or fictitious name to mislead people about where it comes from.
How does an Illinois LLC or corporation file?
The Secretary of State's guide to organizing an LLC lists Form LLC-1.20, Application to Adopt an Assumed Name, in its fee table. Its note says the fee changes with the year of filing, on a repeating cycle:
- $150 if the year ends in 0 or 5
- $120 if it ends in 1 or 6
- $90 if it ends in 2 or 7
- $60 if it ends in 3 or 8
- $30 if it ends in 4 or 9
The same table prices a renewal at $150, a transfer at $25 and a cancellation at $5. Corporations file Form BCA-4.15/4.20 on the same fee cycle, and the corporation guide lists $25 to change an assumed corporate name and $5 to cancel one. Both guides say an assumed name an LLC or corporation adopts voluntarily does not need the entity ending. The LLC guide and the corporation guide have the forms.
How do I search for an Illinois DBA?
Start with the Secretary of State's business search page. It describes the Corporation/LLC Entity Database, which shows a file detail report and lets you check a company name. A sole owner's certificate is a county record, so call or visit the County Clerk where that person operates. Our LLC name search guide covers checking a name before you file.
The state's LLC guide adds a warning: its name decisions are made without regard to sole proprietorships, trade names and the like. So a clean state search result says nothing about a county DBA.
What this page leaves out
We did not read county fee schedules, so we quote no clerk fees. Newspaper rates vary by paper. Ask the clerk about the form and the cost before you file. If you plan a company, see how to start an Illinois LLC and the Illinois business license guide. The step by step is in how to file a DBA.