How to name your LLC: suffixes, restricted words and checking the register

The name has to show what kind of company it is, with one of the suffixes in the table. Most founders use plain LLC, which both states accept. A corporation uses a word such as Corporation, Incorporated or Company, or its abbreviation. The suffix is part of the legal name and goes on every document, but you can trade under a shorter name by registering a trade name.

Your name has to be distinguishable from every name already on the state's register, active or reserved. The test is literal: a different suffix, punctuation, spacing or capitalisation doesn't count. Acme LLC and Acme, L.L.C. are the same name, while Acme Labs LLC is a different one. The state makes the call when the filing arrives, not before.

Delaware has one way round it: if the company that holds the name gives written consent, and the consent is filed with the state, you can register a name that would otherwise be too close. That's useful when a related company, such as your company at home, already has the name.

Words that suggest a regulated activity need the regulator's consent. They include bank and insurance; university, college and academy; licensed professions such as engineer, architect and attorney; and anything that sounds like a government body. Delaware's LLC law bars "bank" outright, unless the company is a bank or the word clearly has nothing to do with banking, as in River Bank Studio. It allows words such as Company, Fund and Trust. Our order form flags these words as you type, so you can drop the word or get the approval before you file.

Both states have a free online search: Wyoming's business search and Delaware's entity search. Search for the distinctive part of your name without the suffix, and look for anything the state might treat as the same. Neither state gives a binding answer in advance. The search shows what's on the register today, and the state decides when your filing arrives.

Forming an LLC puts the name on one state's register and nothing more. It doesn't stop a business in another state from using the same name, and it gives you no rights in the brand. A federal trademark registration from the USPTO does, for the goods or services it covers, and Amazon Brand Registry and most marketplaces rely on registered trademarks. Search the USPTO's trademark database before you settle on a brand, because a name that's free in Wyoming but already a trademark is one you may have to give up. Trademark basics covers filing one from abroad.

• Your company at home can share the name. A US state checks only its own register. Add the suffix, so Acme Ltd becomes Acme LLC.
• Use the legal name exactly at the bank. Mercury, Stripe and the IRS compare what you enter with the name on your articles, suffix included. A trade name goes in a separate field, if they offer one.
• Plain letters travel best. Accented letters and symbols can be read differently by the state, the IRS and the bank, which slows things down.
• Spell it the way it sounds. You'll read it out to banks and clients on calls.

A name can be changed by filing an amendment to the articles: $60 in Wyoming and $220 in Delaware. The EIN stays the same, but you tell the IRS, the bank and every platform, so it's cheaper to get the name right the first time. Amending your articles covers who to tell.

• Distinctive enough to be available and easy to find. Two common words are usually taken; an invented word usually isn't.
• With a .com, or another domain you're happy with, checked the same day.
• Not tied to one product or one country, unless you want it to be.
• With two backups, in case the first is taken.