If you are doing business in New Hampshire and you are not a corporation or a limited liability company, you may need to register your business name with the Secretary of State. Every individual and all associations and partnerships doing business under a name other than that granted by a certificate of authority, certificate of formation or articles of incorporation must register.
Using your own first and last name, however, does not require registration. For example, "John Doe, Contractor", need not be registered; "Doe Construction" must be. If you do not register, you do not have the authority to conduct any business, including advertising. To register a trade name, you must file NH Form No. 9, Application for Registration of Trade Name and pay a $50 filing fee.
Once the trade name is registered, you own that name for five (5) years, at which time the state will send you a re-registration form. It is just as important to retain ownership of the trade name that you have worked so hard to establish and carry on throughout the community. If you do not re-register, your registration will be discontinued and the name thereby abandoned and free for someone else to use.