United States: fifty registers and no national one
Businesses in the United States are formed under state law, in whichever state the founders choose. There is no federal company register, and no national check that a corporate name is unique. A name accepted in Delaware says nothing about Texas. None of the state registers says anything about trademarks, which are a separate federal and state system.
The state entity register in each state where you form or register the business. Trademark rights: federal registrations at the USPTO, state registrations, and unregistered common-law rights from use. Assumed-name (DBA) filings if you trade under a name other than the legal one. Passing one tells you nothing about the others.
The standard most states apply
Most states require a new entity's name to be distinguishable upon the records of the Secretary of State, or similar wording, from names already on the register and names currently reserved. This standard comes from the Model Business Corporation Act, on which many state statutes are based. Delaware's corporation statute uses it (8 Del. C. § 102(a)(1)), as does its LLC statute (6 Del. C. § 18-102). Texas adopted it in 2018, replacing an older “deceptively similar” test.
“Distinguishable” is a narrow, mechanical comparison. It is about whether two records can be told apart, not about whether consumers would be confused. Filing offices typically ignore the entity designator, articles such as “the”, punctuation, and sometimes plurals. The exact rules are set by each state and published in its filing guidance. A name that differs from an existing entity only by “Inc.” versus “LLC” will usually be rejected. A name that differs by one real word will usually be accepted, even if it is commercially confusing.
That narrowness is the main trap. A state accepting your name means only that it is not a near-duplicate on that state's record. It is not a finding that the name is free to use.
Designators: the words the name must contain
| Entity | Typical required word |
|---|---|
| Corporation | Corporation, Incorporated, Company or Limited, or an abbreviation such as Corp., Inc., Co. or Ltd. |
| Limited liability company | Limited Liability Company, or LLC or L.L.C. |
| Limited partnership | Limited Partnership, or LP or L.P. |
| Professional entities | Often a separate designator such as PC, PLLC or Professional Corporation, with licensing conditions attached |
States also restrict particular words. “Bank”, “trust”, “insurance” and words implying a government connection usually need regulatory approval or are reserved for regulated entities. Professional terms, such as those for law, medicine and engineering, are commonly tied to licensing. Delaware, for example, restricts “bank” and its variations to supervised banks. The restricted lists vary by state, and the filing office's guidance is the place to check.
Reserving a name
Most states let you reserve an available name for a fixed period before forming the entity, for a fee. Under the Model Act the reservation period is 120 days. Delaware also reserves for 120 days, while other states set different periods and fees. A reservation holds the name on that state's record only. It gives no rights anywhere else and expires if you do not form the entity in time.
Operating in a second state
A company formed in one state that does business in another usually has to register as a foreign entity there, often called foreign qualification. The name must then pass the second state's distinguishability check too. If it does not, the business usually has to adopt a fictitious name or assumed name for use in that state. That is a common surprise for companies formed in Delaware and operating somewhere with a crowded register.
Assumed names and DBAs
Trading under any name other than the exact legal name, such as a brand, a product line or a shortened form, generally requires an assumed-name or “doing business as” filing. Depending on the state, this is filed with the state, the county, or both. Assumed-name filings exist mainly so the public can find out who is behind a trading name. In most states they do not stop someone else using the same name, and they create no trademark rights.
Where trademarks come in
Trademark rights come from use in commerce and from registration with the USPTO or a state trademark office. The Secretary of State's entity register is not part of that system. A company can be formed under a name that infringes someone's federal trademark, and the filing office will not object, because checking that is not its job. The trademark owner can still sue for infringement. A court can order the company to stop using the name, whatever the corporate register says.
Before you form an entity under a name you plan to build a brand on, run the trademark checks too: the USPTO register, state registers where relevant, and a search for unregistered use. Searching the registers covers how, and rights without registration covers what the registers miss.
Questions
Is there a national search for US company names?
No official one. Each state runs its own entity search, usually free on the Secretary of State's website. Commercial databases combine state records, but they are not the authority. Check the specific state register before filing.
Does forming the company in my name stop a competitor using it?
Not by itself. Entity registration stops a near-identical entity name on that state's record, and nothing more. Stopping a competitor using the name in trade depends on trademark rights, which come from use and from USPTO or state registration.
Can I get a name that is already taken if the other company agrees?
In many states, yes. Statutes often allow an otherwise-unavailable name with the written consent of the existing holder, sometimes combined with an undertaking by that holder to change its own name. Delaware's statute includes a consent route. Check the specific state's rules and forms.
Related
- Delaware entity namesThe statute, the reservation and the restricted words
- Rights without registrationCommon-law rights from use
- The pre-commit checklistRunning the checks in the right order
Published 2026-10-18. An outline of how state entity-name systems work, checked against the Delaware Code and published state guidance. Rules, fees and reservation periods differ by state. Confirm with the filing office of the state concerned. Not legal advice.